Vouch Proxy: Unbounded Multipart Cookie Allocation DoS

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55149
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-15 17:17:21 UTC
Updated2026-09-30 17:51:56 UTC
DescriptionVouch 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.007180000 probability, percentile 0.522050000 (date 2026-10-04)

Problem Types: CWE-789 | CWE-789 CWE-789: Memory Allocation with Excessive Size Value

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Vouch Vouch-proxy affected < 0.48.0 Not specified

References

ReferenceSourceLinkTags
github.com/vouch/vouch-proxy/security/advisories/GHSA-qqff-5854-px68 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/vouch/vouch-proxy/releases/tag/v0.48.0 [email protected] github.com
github.com/vouch/vouch-proxy/commit/fa18ce30ba50a4863a436acad044c2296532... [email protected] github.com
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