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TI-2026-37028 Aliases CVE-2026-50285GHSA-ggw3-5987-rx77

Pomerium: Pre-Auth Memory Exhaustion via Unbounded zstd Decompression in HPKE Callback

Priority HIGH 72CWE-1284Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-770.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00741 54th percentileScored 2026-11-07
Fix Fixed pomerium (pomerium): 0.32.8github.com/pomerium/pomerium (Go): 0.32.8

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
pomeriumpomeriumbefore 0.32.80.32.8Patch availableCNA
—github.com/pomerium/pomerium (Go)0.32.6 to before 0.32.80.32.8Patch availableGHSA-ggw3-5987-rx77
  • pomerium Vendorpomerium Affected before 0.32.8 Fixed in 0.32.8 Patch available CNA
  • github.com/pomerium/pomerium (Go) Vendor— Affected 0.32.6 to before 0.32.8 Fixed in 0.32.8 Patch available GHSA-ggw3-5987-rx77

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:pomerium:pomerium:*:*:*:*:*:*:*:*——pomerium
  • cpe:2.3:a:pomerium:pomerium:*:*:*:*:*:*:*:* Versions — — ·pomerium

Remediation

  • Fix · CNA pomerium (pomerium) Fixed in 0.32.8
  • Fix · GHSA-ggw3-5987-rx77 github.com/pomerium/pomerium (Go) Fixed in 0.32.8 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-50285
  2. 2026-10-03 Alias added: GHSA-ggw3-5987-rx77

References

Other 4

  • TI-2023-16366 Incorrect Authorization with specially crafted requests CVSS 3.1CRITICAL 10.0
  • TI-2022-08610 Exposure of Sensitive Information in Pomerium CVSS 3.1CRITICAL 9.1
  • TI-2021-16548 Incorrect handling of H2 GOAWAY + SETTINGS frames CVSS 3.1HIGH 8.6
  • TI-2021-18069 OIDC claims not updated from Identity Provider in Pomerium CVSS 3.1HIGH 8.8
  • TI-2021-16591 Incorrect Authorization with specially crafted requests CVSS 3.1HIGH 8.6
  • TI-2021-16589 Excessive CPU usage in Pomerium CVSS 3.1HIGH 7.5
See all 10 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences