Vulnerability Description
Pomerium is an identity and context-aware access proxy. Prior to 0.32.8, decodeQueryStringV2 in pkg/hpke/url.go performs zstd decompression of attacker-controlled data without an output-memory limit when DecryptURLValues processes HPKE V2 values for Stateless.Callback in internal/authenticateflow/stateless.go. In hosted or stateless authentication deployments, an unauthenticated attacker can obtain the receiver key from /.well-known/pomerium/hpke-public-key, provide a matching attacker-controlled sender key, and send a compressed payload to /.pomerium/callback that expands before validateSenderPublicKey rejects the sender. This can allocate hundreds of megabytes per request, exhaust proxy memory, crash or degrade the process, and block access to applications protected by the deployment. Stateful deployments are not affected because the stateful callback verifies its HMAC signature before decryption and decompression. This issue is fixed in version 0.32.8.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/pomerium/pomerium/commit/593eb81c7e5bdbe6071a30d330f374967869
- https://github.com/pomerium/pomerium/releases/tag/v0.32.8
- https://github.com/pomerium/pomerium/security/advisories/GHSA-ggw3-5987-rx77
- https://github.com/pomerium/pomerium/security/advisories/GHSA-ggw3-5987-rx77
FAQ
What is CVE-2026-50285?
CVE-2026-50285 is a vulnerability with a CVSS score of 7.5 (HIGH). Pomerium is an identity and context-aware access proxy. Prior to 0.32.8, decodeQueryStringV2 in pkg/hpke/url.go performs zstd decompression of attacker-controlled data without an output-memory limit w...
How severe is CVE-2026-50285?
CVE-2026-50285 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-50285?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.