CVE Catalog

CVE-2026-55149

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Elevated risk
0.72%

52th percentile - higher than 52% of all known CVEs

Summary

Vouch Proxy prior to 0.48.0 parses the total part count from an attacker-controlled multipart cookie name and passes it to make([]string, numParts) without checking that the value is positive or reasonably bounded. A cookie name such as VouchCookie_1of10000000000 causes an attempted allocation of roughly 160 GB and a fatal Go out-of-memory condition.

Risk Assessment

A single request can crash the authentication proxy, and repeated requests can sustain unavailability. The attack requires no account or valid session.

Recommendation

Upgrade Vouch Proxy to version 0.48.0 or later. Until then, consider restricting access to /validate and /_external-auth-:id endpoints and monitoring for unusual requests.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS