CVE-2026-77775

HIGHPre-NVD 8.68.6
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2026-08-21. The CNA's CVSS baseline 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: the CNA's CVSS, EPSS, GitHub Security Advisory

Also known asEUVD-2026-63904 (ENISA EUVD) · GHSA-4j5r-9p93-j2px (GitHub Security Advisories)Source: ENISA EUVD

8.6EG
EchelonGraph verdictPlan mitigationNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.6Exploit: None knownExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. _resolve_openai_upstream_base in headroom/proxy/handlers/openai.py accepts the header value, requires only that it parse with an http or https scheme and a hostname, and returns it for use as the upstream base; _select_passthrough_base_url in headroom/providers/proxy_routes.py reads the same header for the passthrough routes. No check rejects loopback, link-local, or RFC 1918 destinations, and because the component is a proxy the upstream response is returned to the caller, so the request reaches internal services and cloud metadata addresses and their responses are disclosed. The Authorization header accompanying the request is forwarded unchanged to the caller-designated host. The pip console script binds 127.0.0.1 by default, but the reference docker-compose.yml ships --host 0.0.0.0 with published ports and no required HEADROOM_PROXY_TOKEN, which the server itself warns about at startup, so a deployment following the shipped compose exposes the affected data-plane routes to the network without authentication.

CVSS v3
8.6
EG Score
8.6HIGHmedium confidence
EG Risk
54
EG Risk 54/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity86% × 45%
Impact severity (EG Severity): CVSS 8.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
48th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (8.6): severity, escalated by confirmed exploitation. This CVE's 8.6 is its impact severity (EG Severity), not escalated.

EG Severity
8.6 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-07). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 21, 2026

Last Modified

November 8, 2026

Advisory Details (5)

Auto-updated Aug 21, 2026
Fix referenced — no release confirmed yet. Sources: github_pr.
Web page

Headroom Proxy Sends Upstream Requests to a Client-Supplied Base URL Without Address Validation | Advisories | VulnCheck

https://www.vulncheck.com/advisories/headroom-proxy-sends-upstream-requests-to-a-client-supplied-base-url-without-address-validation
Web pageMentions a patch (unverified)

GitHub - headroomlabs-ai/headroom: Compress tool outputs, logs, files, and RAG chunks before they reach the LLM. 20% fewer tokens for coding agents, 60-95% fewer tokens for JSON, same answers. Library, proxy, MCP server. · GitHub

https://github.com/headroomlabs-ai/headroom
Web page

headroom/headroom/proxy/upstream_guard.py at v0.36.1 · headroomlabs-ai/headroom · GitHub

https://github.com/headroomlabs-ai/headroom/blob/v0.36.1/headroom/proxy/upstream_guard.py
Web page

headroom/headroom/proxy/handlers/openai.py at v0.29.0 · headroomlabs-ai/headroom · GitHub

https://github.com/headroomlabs-ai/headroom/blob/v0.29.0/headroom/proxy/handlers/openai.py
GitHub pull request

security: address u9up assessment findings (WEB-01–07)

Fix merged in headroomlabs-ai/headroom PR #2207 on 2026-08-20 — awaiting tagged release

https://github.com/headroomlabs-ai/headroom/pull/2207

Vendor Advisories for CVE-2026-77775(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 35× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 239 rows on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 139 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:57 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  4. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  5. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  6. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  7. 2026-11-08 14:17 UTCEchelonGraph re-scored
  8. 2026-11-08 14:17 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  9. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  10. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  11. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  12. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  13. 2026-11-04 16:21 UTCEchelonGraph re-scored
  14. 2026-11-04 16:21 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  15. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  16. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  17. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  18. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  19. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  20. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  21. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  22. 2026-10-28 07:48 UTCEchelonGraph re-scored
  23. 2026-10-28 07:48 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  24. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  25. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.6% · 48th percentile
Show 75 more
  1. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  2. 2026-10-25 14:01 UTCEchelonGraph re-scored
  3. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  5. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  6. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  7. 2026-10-20 18:20 UTCEchelonGraph re-scored
  8. 2026-10-20 18:20 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  9. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  10. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  11. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  12. 2026-10-18 03:11 UTCEchelonGraph re-scored
  13. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  14. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  15. 2026-10-15 19:29 UTCEchelonGraph re-scored
  16. 2026-10-15 19:28 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  17. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  18. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  19. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  20. 2026-10-13 06:54 UTCEchelonGraph re-scored
  21. 2026-10-13 06:54 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  22. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  23. 2026-10-12 15:37 UTCEchelonGraph re-scored
  24. 2026-10-11 19:23 UTCEchelonGraph re-scored
  25. 2026-10-11 16:39 UTCEchelonGraph re-scored
  26. 2026-10-11 13:57 UTCEchelonGraph re-scored
  27. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  28. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  29. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  30. 2026-10-09 06:00 UTCEchelonGraph re-scored
  31. 2026-10-09 06:00 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  32. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  33. 2026-10-08 04:58 UTCEchelonGraph re-scored
  34. 2026-10-08 04:57 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  35. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  36. 2026-10-07 06:39 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  37. 2026-10-06 19:21 UTCEchelonGraph re-scored
  38. 2026-10-06 19:21 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  39. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  40. 2026-10-06 07:49 UTCEchelonGraph re-scored
  41. 2026-10-06 07:49 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  42. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-10-05 17:07 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  44. 2026-10-05 04:55 UTCEchelonGraph re-scored
  45. 2026-10-05 04:55 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  46. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  47. 2026-10-04 15:39 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  48. 2026-10-04 04:02 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  49. 2026-10-03 16:43 UTCEchelonGraph re-scored
  50. 2026-10-03 16:43 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  51. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  52. 2026-10-02 20:59 UTCEchelonGraph re-scored
  53. 2026-10-02 20:59 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  54. 2026-10-02 08:43 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  55. 2026-10-01 21:25 UTCEchelonGraph re-scored
  56. 2026-10-01 21:25 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  57. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  58. 2026-10-01 07:46 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  59. 2026-09-30 20:29 UTCEchelonGraph re-scored
  60. 2026-09-30 20:29 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  61. 2026-09-30 07:57 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  62. 2026-09-29 16:15 UTCEchelonGraph re-scored
  63. 2026-09-29 16:15 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  64. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  65. 2026-09-29 00:37 UTCEchelonGraph re-scored
  66. 2026-09-29 00:37 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  67. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  68. 2026-09-28 13:19 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  69. 2026-09-28 02:02 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  70. 2026-09-27 14:44 UTCEchelonGraph re-scored
  71. 2026-09-27 14:44 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  72. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  73. 2026-09-27 02:31 UTCEchelonGraph re-scored
  74. 2026-09-27 02:31 UTCGHSA enrichmentGHSA-4j5r-9p93-j2px · GitHub severity HIGH · GitHub CVSS 8.6
  75. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 46th percentile

Frequently asked(5)

What is CVE-2026-77775?
CVE-2026-77775 is a high-severity vulnerability; its CVE record was published on August 21, 2026. Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. _resolve_openai_upstream_base in headroom/proxy/handlers/openai.py accepts the header value, requires only that it parse with an http or https scheme and a hostname, and returns it for…
When was CVE-2026-77775 made public?
CVE-2026-77775 was made public on August 20, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 21, 2026. EchelonGraph's copy of the record carries a last-modified date of November 8, 2026; the record at its source may have been updated since.
Is CVE-2026-77775 actively exploited?
CVE-2026-77775 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (48th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77775?
CVE-2026-77775 has a CVSS base score of 8.6 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-77775?
A fix for CVE-2026-77775 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2026-77775 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-77775

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