CVE-2026-77775

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

Score 8.6 from GitHub Security Advisory (severity: HIGH) published 2026-08-21. a secondary CVSS source baseline 8.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
8.6(medium)
EG Risk
54(Track)
EG Risk 54/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity86% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
30%
KEV
Not listed

Published

August 21, 2026

Last Modified

September 9, 2026

Advisory Details (5)

Auto-updated Aug 21, 2026
Patch available. Sources: github_pr.
generic

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
generic Patch Available

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
generic

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
generic

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_pr

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 29× in last 7d / 116× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 122 total refreshes for this CVE.

  1. 2026-09-21 05:45 UTCEG score recompute
  2. 2026-09-21 05:45 UTCGHSA enrichment
  3. 2026-09-20 20:16 UTCEPSS rescore
  4. 2026-09-20 17:07 UTCEG score recompute
  5. 2026-09-20 17:07 UTCGHSA enrichment
  6. 2026-09-20 05:49 UTCGHSA enrichment
  7. 2026-09-19 18:31 UTCEG score recompute
  8. 2026-09-19 18:31 UTCGHSA enrichment
  9. 2026-09-19 07:14 UTCGHSA enrichment
  10. 2026-09-18 19:56 UTCEG score recompute
  11. 2026-09-18 19:56 UTCGHSA enrichment
  12. 2026-09-18 19:28 UTCEPSS rescore
  13. 2026-09-18 08:36 UTCGHSA enrichment
  14. 2026-09-17 21:17 UTCEG score recompute
  15. 2026-09-17 21:17 UTCGHSA enrichment
  16. 2026-09-17 09:59 UTCGHSA enrichment
  17. 2026-09-16 22:41 UTCEG score recompute
  18. 2026-09-16 22:41 UTCGHSA enrichment
  19. 2026-09-16 14:08 UTCEPSS rescore
  20. 2026-09-16 11:08 UTCEG score recompute
  21. 2026-09-16 11:08 UTCGHSA enrichment
  22. 2026-09-16 05:15 UTCEPSS rescore
  23. 2026-09-15 23:50 UTCGHSA enrichment
  24. 2026-09-15 12:28 UTCEG score recompute
  25. 2026-09-15 12:28 UTCGHSA enrichment
Show 75 more
  1. 2026-09-15 03:12 UTCEPSS rescore
  2. 2026-09-15 03:12 UTCEPSS rescore
  3. 2026-09-15 01:10 UTCGHSA enrichment
  4. 2026-09-14 13:52 UTCGHSA enrichment
  5. 2026-09-14 02:34 UTCEG score recompute
  6. 2026-09-14 02:34 UTCGHSA enrichment
  7. 2026-09-13 15:16 UTCGHSA enrichment
  8. 2026-09-13 03:57 UTCGHSA enrichment
  9. 2026-09-12 16:39 UTCEG score recompute
  10. 2026-09-12 16:39 UTCGHSA enrichment
  11. 2026-09-12 05:21 UTCGHSA enrichment
  12. 2026-09-11 18:03 UTCEG score recompute
  13. 2026-09-11 18:03 UTCGHSA enrichment
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-11 06:45 UTCGHSA enrichment
  16. 2026-09-10 19:27 UTCEG score recompute
  17. 2026-09-10 19:27 UTCGHSA enrichment
  18. 2026-09-10 09:35 UTCEPSS rescore
  19. 2026-09-10 08:08 UTCGHSA enrichment
  20. 2026-09-09 20:50 UTCGHSA enrichment
  21. 2026-09-09 13:06 UTCGHSA enrichment
  22. 2026-09-09 01:48 UTCEG score recompute
  23. 2026-09-09 01:48 UTCGHSA enrichment
  24. 2026-09-08 22:01 UTCEPSS rescore
  25. 2026-09-08 02:46 UTCEG score recompute
  26. 2026-09-08 02:46 UTCGHSA enrichment
  27. 2026-09-07 15:29 UTCGHSA enrichment
  28. 2026-09-07 03:51 UTCGHSA enrichment
  29. 2026-09-06 16:12 UTCEG score recompute
  30. 2026-09-06 16:12 UTCGHSA enrichment
  31. 2026-09-06 13:48 UTCEPSS rescore
  32. 2026-09-06 04:46 UTCGHSA enrichment
  33. 2026-09-05 17:28 UTCEG score recompute
  34. 2026-09-05 17:28 UTCGHSA enrichment
  35. 2026-09-05 06:06 UTCGHSA enrichment
  36. 2026-09-04 18:49 UTCEG score recompute
  37. 2026-09-04 18:48 UTCGHSA enrichment
  38. 2026-09-04 07:12 UTCEG score recompute
  39. 2026-09-04 07:11 UTCGHSA enrichment
  40. 2026-09-04 05:07 UTCEPSS rescore
  41. 2026-09-03 19:44 UTCGHSA enrichment
  42. 2026-09-03 08:24 UTCGHSA enrichment
  43. 2026-09-02 21:07 UTCEG score recompute
  44. 2026-09-02 21:06 UTCGHSA enrichment
  45. 2026-09-02 14:12 UTCEPSS rescore
  46. 2026-09-02 07:15 UTCGHSA enrichment
  47. 2026-09-01 19:53 UTCEG score recompute
  48. 2026-09-01 19:53 UTCGHSA enrichment
  49. 2026-09-01 13:54 UTCEPSS rescore
  50. 2026-09-01 08:35 UTCEG score recompute
  51. 2026-09-01 08:35 UTCGHSA enrichment
  52. 2026-09-01 04:40 UTCEPSS rescore
  53. 2026-09-01 04:40 UTCEPSS rescore
  54. 2026-08-31 21:11 UTCGHSA enrichment
  55. 2026-08-31 09:49 UTCGHSA enrichment
  56. 2026-08-30 22:31 UTCEG score recompute
  57. 2026-08-30 22:31 UTCGHSA enrichment
  58. 2026-08-30 19:18 UTCEPSS rescore
  59. 2026-08-30 19:17 UTCEPSS rescore
  60. 2026-08-30 11:14 UTCEG score recompute
  61. 2026-08-30 11:14 UTCGHSA enrichment
  62. 2026-08-30 01:22 UTCEPSS rescore
  63. 2026-08-29 23:56 UTCGHSA enrichment
  64. 2026-08-29 12:38 UTCGHSA enrichment
  65. 2026-08-29 01:17 UTCEG score recompute
  66. 2026-08-29 01:16 UTCGHSA enrichment
  67. 2026-08-28 21:42 UTCEPSS rescore
  68. 2026-08-28 13:51 UTCGHSA enrichment
  69. 2026-08-28 02:29 UTCGHSA enrichment
  70. 2026-08-27 15:11 UTCEG score recompute
  71. 2026-08-27 15:11 UTCGHSA enrichment
  72. 2026-08-27 14:25 UTCEPSS rescore
  73. 2026-08-27 03:53 UTCGHSA enrichment
  74. 2026-08-26 16:35 UTCEG score recompute
  75. 2026-08-26 16:35 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77775?
CVE-2026-77775 is a high vulnerability published on August 21, 2026. Headroom's LLM proxy lets a client choose the upstream destination with the x-headroom-base-url request header. resolveopenaiupstreambase 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…
When was CVE-2026-77775 disclosed?
CVE-2026-77775 was first published in the National Vulnerability Database on August 21, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77775 actively exploited?
CVE-2026-77775 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 69.9% of all scored CVEs.
What is the CVSS score of CVE-2026-77775?
CVE-2026-77775 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-77775?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77775, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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

Explore →

Is Your Infrastructure Affected by CVE-2026-77775?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs