CVE-2026-55149

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7% (52nd percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Vouch Proxy is an SSO and OAuth/OIDC login solution for Nginx using the auth_request module. Prior to 0.48.0, Cookie in pkg/cookie/cookie.go parses the total part count from an attacker-controlled multipart cookie name and passes the value to make([]string, numParts) without checking that the value is positive or reasonably bounded. Requests to /validate and /_external-auth-:id reach JWTCacheHandler in pkg/jwtmanager/jwtcache.go, FindJWT in pkg/jwtmanager/jwtmanager.go, and the vulnerable cookie reassembly before JWT validation, so no account or valid session is required. A cookie name such as VouchCookie_1of10000000000 causes an attempted slice allocation of roughly 160 GB and a fatal Go runtime out-of-memory condition, allowing one request to crash the authentication proxy and repeated requests to sustain unavailability. This vulnerability is fixed in 0.48.0.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100CISA SSVC

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
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.7%
EPSS %ILE
52nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 30, 2026

Advisory Details (2)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github_commit

commit fa18ce30ba50 (vouch/vouch-proxy)

Fix landed in vouch/vouch-proxy commit fa18ce30ba50 — awaiting tagged release

https://github.com/vouch/vouch-proxy/commit/fa18ce30ba50a4863a436acad044c22965329c4f
github Patch Available🟡 PoC Available

Unbounded Multipart Cookie Allocation DoS in vouch-proxy · Advisory · vouch/vouch-proxy · GitHub

https://github.com/vouch/vouch-proxy/security/advisories/GHSA-qqff-5854-px68

Vendor Advisories for CVE-2026-55149(1)

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

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/vouch/vouch-proxy—
  • every version up to 0.48.0: fixed in 0.48.0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 14× in last 7d / 36× 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. 2026-10-05 09:29 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-03 16:47 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 21:35 UTCEG score recompute
  6. 2026-10-02 17:56 UTCEPSS rescore
  7. 2026-10-01 21:29 UTCEG score recompute
  8. 2026-10-01 19:50 UTCEPSS rescore
  9. 2026-09-30 18:10 UTCEG score recompute
  10. 2026-09-30 15:03 UTCEPSS rescore
  11. 2026-09-30 08:14 UTCEG score recompute
  12. 2026-09-29 15:22 UTCEPSS rescore
  13. 2026-09-29 03:54 UTCEG score recompute
  14. 2026-09-28 16:03 UTCEG score recompute
  15. 2026-09-28 13:51 UTCEPSS rescore
  16. 2026-09-27 15:57 UTCEG score recompute
  17. 2026-09-27 13:48 UTCEPSS rescore
  18. 2026-09-27 03:02 UTCEG score recompute
  19. 2026-09-26 15:59 UTCEPSS rescore
  20. 2026-09-24 19:46 UTCEG score recompute
  21. 2026-09-24 14:04 UTCEPSS rescore
  22. 2026-09-23 20:05 UTCEG score recompute
  23. 2026-09-23 17:54 UTCEPSS rescore
  24. 2026-09-22 19:45 UTCEG score recompute
  25. 2026-09-22 05:44 UTCEG score recompute
Show 12 more
  1. 2026-09-21 05:48 UTCEG score recompute
  2. 2026-09-20 20:16 UTCEPSS rescore
  3. 2026-09-19 17:35 UTCEG score recompute
  4. 2026-09-19 05:45 UTCEG score recompute
  5. 2026-09-18 19:28 UTCEPSS rescore
  6. 2026-09-18 06:03 UTCEG score recompute
  7. 2026-09-17 19:31 UTCEPSS rescore
  8. 2026-09-17 18:13 UTCEG score recompute
  9. 2026-09-16 20:02 UTCEG score recompute
  10. 2026-09-16 14:08 UTCEPSS rescore
  11. 2026-09-15 17:34 UTCEG score recompute
  12. 2026-08-20 17:42 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55149?
CVE-2026-55149 is a high vulnerability published on August 20, 2026. Vouch Proxy is an SSO and OAuth/OIDC login solution for Nginx using the authrequest module. Prior to 0.48.0, Cookie in pkg/cookie/cookie.go parses the total part count from an attacker-controlled multipart cookie name and passes the value to make([]string, numParts) without checking that the value…
When was CVE-2026-55149 disclosed?
CVE-2026-55149 was first published on August 20, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55149 actively exploited?
CVE-2026-55149 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (52nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55149?
CVE-2026-55149 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55149?
A fix for CVE-2026-55149 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55149 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55149

Explore →

Is Your Infrastructure Affected by CVE-2026-55149?

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

Book a Demo →Browse All CVEs