CVE-2026-58055

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreHIGH confidence

Score 5.4 from GitHub Security Advisory published 2026-06-28. a secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: None knownExposed: 0

A fix is available — apply it.

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.

CVSS v3
5.4
EG Score
5.4(high)
EG Risk
24(Track)
EG Risk 24/100SSVC: 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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
10%
KEV
Not listed

Published

June 28, 2026

Last Modified

June 30, 2026

Advisory Details (3)

Auto-updated Jun 28, 2026
🔬 Proof of concept available. Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic🟡 PoC Available

nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nghttp2-nghttpx-http-request-response-smuggling-via-upgrade-request-with-content-length
github_commit

commit ab28105c4a01 (nghttp2/nghttp2)

Fix landed in nghttp2/nghttp2 commit ab28105c4a01 — awaiting tagged release

https://github.com/nghttp2/nghttp2/commit/ab28105c4a0197da24f8bfc414bc116055249e1e
generic

exploitarium/nghttp2-nghttpx-upgrade-queue-poison-poc at main · bikini/exploitarium · GitHub

https://github.com/bikini/exploitarium/tree/main/nghttp2-nghttpx-upgrade-queue-poison-poc

Vendor Advisories for CVE-2026-58055(4)

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

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntunghttp2-server (1.59.0-1ubuntu0.4) @ noble2026-07-27ubuntu
redhatcurl-main-8.21.0-0.1.1.hum12026-07-17redhat
redhatnghttp2-main-1.69.0-3.1.hum12026-07-03redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 19× in last 7d / 93× 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.

  1. 2026-07-27 14:14 UTCEPSS rescore
  2. 2026-07-27 12:12 UTCEG score recompute
  3. 2026-07-27 12:12 UTCVendor advisory
  4. 2026-07-27 12:12 UTCGHSA enrichment
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-26 14:25 UTCEG score recompute
  8. 2026-07-26 14:25 UTCVendor advisory
  9. 2026-07-26 14:25 UTCGHSA enrichment
  10. 2026-07-25 14:18 UTCEPSS rescore
  11. 2026-07-25 14:18 UTCEPSS rescore
  12. 2026-07-24 14:18 UTCEPSS rescore
  13. 2026-07-24 14:18 UTCEPSS rescore
  14. 2026-07-23 14:18 UTCEPSS rescore
  15. 2026-07-23 14:18 UTCEPSS rescore
  16. 2026-07-23 03:20 UTCEG score recompute
  17. 2026-07-22 14:08 UTCEPSS rescore
  18. 2026-07-22 14:08 UTCEPSS rescore
  19. 2026-07-21 15:25 UTCEPSS rescore
  20. 2026-07-20 17:08 UTCEPSS rescore
  21. 2026-07-19 14:31 UTCEPSS rescore
  22. 2026-07-19 14:31 UTCEPSS rescore
  23. 2026-07-19 02:29 UTCEPSS rescore
  24. 2026-07-18 10:04 UTCEPSS rescore
  25. 2026-07-17 03:55 UTCVendor advisory
Show 68 more
  1. 2026-07-17 03:55 UTCGHSA enrichment
  2. 2026-07-16 17:03 UTCEPSS rescore
  3. 2026-07-16 06:08 UTCVendor advisory
  4. 2026-07-16 06:07 UTCGHSA enrichment
  5. 2026-07-15 16:57 UTCEPSS rescore
  6. 2026-07-15 16:57 UTCEPSS rescore
  7. 2026-07-15 08:19 UTCVendor advisory
  8. 2026-07-15 08:19 UTCGHSA enrichment
  9. 2026-07-15 02:00 UTCEPSS rescore
  10. 2026-07-15 02:00 UTCEPSS rescore
  11. 2026-07-14 10:31 UTCVendor advisory
  12. 2026-07-14 10:31 UTCGHSA enrichment
  13. 2026-07-13 22:31 UTCEPSS rescore
  14. 2026-07-13 12:44 UTCVendor advisory
  15. 2026-07-13 12:44 UTCGHSA enrichment
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-12 14:57 UTCVendor advisory
  19. 2026-07-12 14:57 UTCGHSA enrichment
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 17:10 UTCVendor advisory
  22. 2026-07-11 17:10 UTCGHSA enrichment
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-11 08:27 UTCEPSS rescore
  25. 2026-07-10 19:22 UTCVendor advisory
  26. 2026-07-10 19:22 UTCGHSA enrichment
  27. 2026-07-09 21:34 UTCVendor advisory
  28. 2026-07-09 21:34 UTCGHSA enrichment
  29. 2026-07-09 19:10 UTCEPSS rescore
  30. 2026-07-09 19:10 UTCEPSS rescore
  31. 2026-07-08 23:46 UTCVendor advisory
  32. 2026-07-08 23:46 UTCGHSA enrichment
  33. 2026-07-08 15:16 UTCEPSS rescore
  34. 2026-07-08 15:16 UTCEPSS rescore
  35. 2026-07-08 01:59 UTCVendor advisory
  36. 2026-07-08 01:59 UTCGHSA enrichment
  37. 2026-07-07 13:46 UTCEPSS rescore
  38. 2026-07-07 13:46 UTCEPSS rescore
  39. 2026-07-07 04:12 UTCVendor advisory
  40. 2026-07-07 04:12 UTCGHSA enrichment
  41. 2026-07-06 16:27 UTCEPSS rescore
  42. 2026-07-06 16:27 UTCEPSS rescore
  43. 2026-07-06 06:22 UTCVendor advisory
  44. 2026-07-06 06:22 UTCGHSA enrichment
  45. 2026-07-06 02:23 UTCEPSS rescore
  46. 2026-07-06 02:23 UTCEPSS rescore
  47. 2026-07-05 08:33 UTCVendor advisory
  48. 2026-07-05 08:33 UTCGHSA enrichment
  49. 2026-07-05 02:31 UTCEPSS rescore
  50. 2026-07-05 02:30 UTCEPSS rescore
  51. 2026-07-04 10:46 UTCVendor advisory
  52. 2026-07-04 10:46 UTCGHSA enrichment
  53. 2026-07-04 06:31 UTCEPSS rescore
  54. 2026-07-04 06:31 UTCEPSS rescore
  55. 2026-07-03 12:58 UTCVendor advisory
  56. 2026-07-03 12:58 UTCGHSA enrichment
  57. 2026-07-02 15:11 UTCVendor advisory
  58. 2026-07-02 15:10 UTCGHSA enrichment
  59. 2026-07-01 17:20 UTCGHSA enrichment
  60. 2026-07-01 15:07 UTCEPSS rescore
  61. 2026-06-30 23:22 UTCEPSS rescore
  62. 2026-06-30 19:33 UTCGHSA enrichment
  63. 2026-06-29 21:46 UTCGHSA enrichment
  64. 2026-06-29 14:06 UTCEPSS rescore
  65. 2026-06-28 23:58 UTCGHSA enrichment
  66. 2026-06-28 14:07 UTCEPSS rescore
  67. 2026-06-28 02:10 UTCEG score recompute
  68. 2026-06-28 02:09 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-58055?
CVE-2026-58055 is a medium vulnerability published on June 28, 2026. nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting…
When was CVE-2026-58055 disclosed?
CVE-2026-58055 was first published in the National Vulnerability Database on June 28, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-58055 actively exploited?
CVE-2026-58055 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 89.6% of all scored CVEs.
What is the CVSS score of CVE-2026-58055?
CVE-2026-58055 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-58055?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-58055, 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-2026-58055

Explore →

Is Your Infrastructure Affected by CVE-2026-58055?

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

Start Free Scan →Browse All CVEs