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
5.4
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.4Exploit: NoneExposed: 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)
EPSS
10.3%
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(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntunghttp2-server (1.68.0-2ubuntu0.2) @ resolute2026-07-07ubuntu

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.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 32× in last 7d / 40× 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. 2026-07-07 04:12 UTCEG score recompute
  2. 2026-07-07 04:12 UTCVendor advisory
  3. 2026-07-07 04:12 UTCGHSA enrichment
  4. 2026-07-06 16:27 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 06:22 UTCEG score recompute
  7. 2026-07-06 06:22 UTCVendor advisory
  8. 2026-07-06 06:22 UTCGHSA enrichment
  9. 2026-07-06 02:23 UTCEPSS rescore
  10. 2026-07-06 02:23 UTCEPSS rescore
  11. 2026-07-05 08:33 UTCEG score recompute
  12. 2026-07-05 08:33 UTCVendor advisory
  13. 2026-07-05 08:33 UTCGHSA enrichment
  14. 2026-07-05 02:31 UTCEPSS rescore
  15. 2026-07-05 02:30 UTCEPSS rescore
  16. 2026-07-04 10:46 UTCEG score recompute
  17. 2026-07-04 10:46 UTCVendor advisory
  18. 2026-07-04 10:46 UTCGHSA enrichment
  19. 2026-07-04 06:31 UTCEPSS rescore
  20. 2026-07-04 06:31 UTCEPSS rescore
  21. 2026-07-03 12:58 UTCEG score recompute
  22. 2026-07-03 12:58 UTCVendor advisory
  23. 2026-07-03 12:58 UTCGHSA enrichment
  24. 2026-07-02 15:11 UTCEG score recompute
  25. 2026-07-02 15:11 UTCVendor advisory
Show 15 more
  1. 2026-07-02 15:10 UTCGHSA enrichment
  2. 2026-07-01 17:20 UTCEG score recompute
  3. 2026-07-01 17:20 UTCGHSA enrichment
  4. 2026-07-01 15:07 UTCEPSS rescore
  5. 2026-06-30 23:22 UTCEPSS rescore
  6. 2026-06-30 19:33 UTCEG score recompute
  7. 2026-06-30 19:33 UTCGHSA enrichment
  8. 2026-06-29 21:46 UTCEG score recompute
  9. 2026-06-29 21:46 UTCGHSA enrichment
  10. 2026-06-29 14:06 UTCEPSS rescore
  11. 2026-06-28 23:58 UTCEG score recompute
  12. 2026-06-28 23:58 UTCGHSA enrichment
  13. 2026-06-28 14:07 UTCEPSS rescore
  14. 2026-06-28 02:10 UTCEG score recompute
  15. 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 10.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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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