CVE-2026-58055

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM 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 — Patch released 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(medium)
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
18%
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(8)

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

Patch Availability(7)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntunghttp2-server (1.68.0-2ubuntu0.2) @ resolute2026-08-20ubuntu
redhatnghttp2-0:1.33.0-6.el8_10.32026-08-17redhat
redhatnghttp2-0:1.43.0-6.el9_8.22026-08-13redhat
redhatnghttp2-0:1.68.0-3.el10_2.22026-08-13redhat
redhatnghttp2-main-1.69.0-5.hum12026-08-10redhat
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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
nghttp21.43.0-1 ... 1.70.0-1 (30 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
nghttp21.52.0-1 ... 1.70.0-1 (23 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
nghttp21.64.0-1.1 ... 1.70.0-1 (7 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
nghttp21.64.0-1.1 ... 1.70.0-1 (6 versions)——

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 25× in last 7d / 112× 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 187 total refreshes for this CVE.

  1. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 06:02 UTCEG score recompute
  3. 2026-08-20 06:02 UTCVendor advisory
  4. 2026-08-20 06:02 UTCGHSA enrichment
  5. 2026-08-19 17:04 UTCEPSS rescore
  6. 2026-08-18 23:23 UTCEG score recompute
  7. 2026-08-18 23:23 UTCVendor advisory
  8. 2026-08-18 23:23 UTCGHSA enrichment
  9. 2026-08-18 13:48 UTCEPSS rescore
  10. 2026-08-17 13:47 UTCEPSS rescore
  11. 2026-08-17 12:43 UTCEG score recompute
  12. 2026-08-17 12:43 UTCVendor advisory
  13. 2026-08-17 12:43 UTCGHSA enrichment
  14. 2026-08-16 14:56 UTCEPSS rescore
  15. 2026-08-16 14:56 UTCEG score recompute
  16. 2026-08-16 14:56 UTCVendor advisory
  17. 2026-08-16 14:56 UTCGHSA enrichment
  18. 2026-08-16 02:14 UTCEPSS rescore
  19. 2026-08-15 17:09 UTCEG score recompute
  20. 2026-08-15 17:09 UTCVendor advisory
  21. 2026-08-15 17:09 UTCGHSA enrichment
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 19:22 UTCEG score recompute
  24. 2026-08-14 19:22 UTCVendor advisory
  25. 2026-08-14 19:22 UTCGHSA enrichment
Show 75 more
  1. 2026-08-13 22:00 UTCEPSS rescore
  2. 2026-08-13 21:30 UTCVendor advisory
  3. 2026-08-13 21:30 UTCGHSA enrichment
  4. 2026-08-12 23:37 UTCEG score recompute
  5. 2026-08-12 23:37 UTCVendor advisory
  6. 2026-08-12 23:37 UTCGHSA enrichment
  7. 2026-08-12 13:51 UTCEPSS rescore
  8. 2026-08-12 01:50 UTCEG score recompute
  9. 2026-08-12 01:50 UTCVendor advisory
  10. 2026-08-12 01:50 UTCGHSA enrichment
  11. 2026-08-11 04:03 UTCEG score recompute
  12. 2026-08-11 04:03 UTCVendor advisory
  13. 2026-08-11 04:03 UTCGHSA enrichment
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 06:16 UTCEG score recompute
  16. 2026-08-10 06:16 UTCVendor advisory
  17. 2026-08-10 06:16 UTCGHSA enrichment
  18. 2026-08-09 13:46 UTCEPSS rescore
  19. 2026-08-09 08:29 UTCEG score recompute
  20. 2026-08-09 08:29 UTCVendor advisory
  21. 2026-08-09 08:29 UTCGHSA enrichment
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-08 10:41 UTCEG score recompute
  24. 2026-08-08 10:41 UTCVendor advisory
  25. 2026-08-08 10:41 UTCGHSA enrichment
  26. 2026-08-07 12:54 UTCVendor advisory
  27. 2026-08-07 12:54 UTCGHSA enrichment
  28. 2026-08-06 15:07 UTCEG score recompute
  29. 2026-08-06 15:07 UTCVendor advisory
  30. 2026-08-06 15:07 UTCGHSA enrichment
  31. 2026-08-06 13:47 UTCEPSS rescore
  32. 2026-08-05 19:17 UTCEPSS rescore
  33. 2026-08-05 17:20 UTCVendor advisory
  34. 2026-08-05 17:20 UTCGHSA enrichment
  35. 2026-08-04 19:33 UTCEG score recompute
  36. 2026-08-04 19:33 UTCVendor advisory
  37. 2026-08-04 19:33 UTCGHSA enrichment
  38. 2026-08-04 15:10 UTCEPSS rescore
  39. 2026-08-04 10:39 UTCEPSS rescore
  40. 2026-08-03 21:46 UTCEG score recompute
  41. 2026-08-03 21:46 UTCVendor advisory
  42. 2026-08-03 21:46 UTCGHSA enrichment
  43. 2026-08-03 10:36 UTCEPSS rescore
  44. 2026-08-02 23:58 UTCEG score recompute
  45. 2026-08-02 23:58 UTCVendor advisory
  46. 2026-08-02 23:58 UTCGHSA enrichment
  47. 2026-08-02 02:27 UTCEPSS rescore
  48. 2026-08-02 02:11 UTCVendor advisory
  49. 2026-08-02 02:11 UTCGHSA enrichment
  50. 2026-08-01 04:24 UTCEG score recompute
  51. 2026-08-01 04:24 UTCVendor advisory
  52. 2026-08-01 04:23 UTCGHSA enrichment
  53. 2026-08-01 04:16 UTCEPSS rescore
  54. 2026-07-31 06:36 UTCEG score recompute
  55. 2026-07-31 06:36 UTCVendor advisory
  56. 2026-07-31 06:36 UTCGHSA enrichment
  57. 2026-07-30 16:28 UTCEPSS rescore
  58. 2026-07-30 08:48 UTCEG score recompute
  59. 2026-07-30 08:48 UTCVendor advisory
  60. 2026-07-30 08:48 UTCGHSA enrichment
  61. 2026-07-30 01:30 UTCEPSS rescore
  62. 2026-07-30 01:30 UTCEPSS rescore
  63. 2026-07-29 08:47 UTCEG score recompute
  64. 2026-07-29 08:47 UTCVendor advisory
  65. 2026-07-29 08:47 UTCGHSA enrichment
  66. 2026-07-28 15:37 UTCEPSS rescore
  67. 2026-07-28 10:03 UTCEG score recompute
  68. 2026-07-28 10:03 UTCVendor advisory
  69. 2026-07-28 10:03 UTCGHSA enrichment
  70. 2026-07-27 14:14 UTCEPSS rescore
  71. 2026-07-27 12:12 UTCEG score recompute
  72. 2026-07-27 12:12 UTCVendor advisory
  73. 2026-07-27 12:12 UTCGHSA enrichment
  74. 2026-07-26 14:54 UTCEPSS rescore
  75. 2026-07-26 14:54 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

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 81.7% 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

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