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 — 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(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
17%
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(14)

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

Patch Availability(13)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntunghttp2-server (1.64.0-1.1ubuntu1.2) @ questing2026-09-18ubuntu
redhatrhui5/rhua-rhel9:17888805812026-09-09redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17883485712026-09-03redhat
redhatcert-manager/cert-manager-istio-csr-rhel9:17883485942026-09-03redhat
redhatcert-manager/cert-manager-operator-rhel9:17883485222026-09-03redhat
redhatdiscovery/discovery-ui-rhel9:17882061962026-08-31redhat
redhatrhui5/rhua-tp-rhel9:17872412602026-08-24redhat
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, 1.68.0-1, 1.68.0-2, 1.68.1-1, 1.69.0-11.70.0-1—

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 14× in last 7d / 55× 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 241 total refreshes for this CVE.

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

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 82.8% 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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