---
id: CVE-2026-55149
title: >-
  Vouch Proxy is an SSO and OAuth/OIDC login solution for Nginx using the
  auth_request module
summary: >-
  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 val…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-789
vendor: vouch
product: vouch-proxy
affected:
  - vouch-proxy < 0.48.0
patched:
  - github.com/vouch/vouch-proxy 0.48.0
published: '2026-09-15'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:16:44.293'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55149'
references:
  - url: >-
      https://github.com/vouch/vouch-proxy/commit/fa18ce30ba50a4863a436acad044c22965329c4f
    label: security-advisories@github.com
  - url: 'https://github.com/vouch/vouch-proxy/releases/tag/v0.48.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/vouch/vouch-proxy/security/advisories/GHSA-qqff-5854-px68
    label: security-advisories@github.com
  - url: >-
      https://github.com/vouch/vouch-proxy/security/advisories/GHSA-qqff-5854-px68
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://github.com/advisories/GHSA-qqff-5854-px68'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - go
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-17T16:05:30.568513Z'
epss: 0.00399
epssPercentile: 0.33897
aliases:
  - GHSA-qqff-5854-px68
ecosystem: go
ingestedAt: '2026-08-20T17:59:05.945Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-55149)

Affected packages:

- `github.com/vouch/vouch-proxy <= 0.47.2`

Patched in:

- `github.com/vouch/vouch-proxy 0.48.0`

Source: https://github.com/advisories/GHSA-qqff-5854-px68