Read the docs
TI-2026-81534 Aliases CVE-2026-116775GHSA-662x-8wvj-2276

Unbounded frame buffering in pageant enables memory exhaustion

Priority MEDIUM 45CWE-770Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-770.

Summary

The pageant crate from 0.2.0 before 0.2.5 is affected, as is the russh crate from 0.2.0 before 0.2.5. PageantStream::new trusts a four-byte length prefix sent by the peer and buffers data until that many bytes arrive, without checking the transport capacity limit (CWE-770). An application that bridges an SSH forwarded-agent channel to the raw stream lets a malicious server force large allocations or hold a partly filled frame, exhausting the client's memory.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

pageant provides a PageantStream type that implements AsyncRead and AsyncWrite traits and can be used to communicate with a running Pageant instance. From 0.2.0 until 0.2.5, PageantStream::new in pageant/src/wmmessage.rs trusts a peer-controlled four-byte length prefix and buffers until len + 4 bytes are available without checking the fixed _AGENT_MAX_MSGLEN transport capacity. An application that bridges an SSH forwarded-agent channel to the raw stream can allow a malicious server to force large allocations or retain a partially filled frame, causing client memory exhaustion. This issue is fixed in version 0.2.5.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00294 22nd percentileScored 2026-11-07
Fix Fixed russh (Eugeny): 0.2.5pageant (crates.io): 0.2.5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
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
Eugenyrussh0.2.0 to before 0.2.50.2.5Patch availableCNA
—pageant (crates.io)0.2.0 to before 0.2.50.2.5Patch availableGHSA-662x-8wvj-2276
  • russh VendorEugeny Affected 0.2.0 to before 0.2.5 Fixed in 0.2.5 Patch available CNA
  • pageant (crates.io) Vendor— Affected 0.2.0 to before 0.2.5 Fixed in 0.2.5 Patch available GHSA-662x-8wvj-2276

Remediation

Upgrade pageant and russh to version 0.2.5, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA russh (Eugeny) Fixed in 0.2.5
  • Fix · GHSA-662x-8wvj-2276 pageant (crates.io) Fixed in 0.2.5 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat Hardened Images

Timeline

  1. 2026-10-27 Threatist record created from CVE-2026-116775
  2. 2026-10-30 Alias added: GHSA-662x-8wvj-2276
  3. 2026-10-30 Fix available: crates.io/[email protected] · GHSA-662x-8wvj-2276
  4. 2026-10-30 CVSS score added · GHSA-662x-8wvj-2276
  5. 2026-10-30 Weakness changed · GHSA-662x-8wvj-2276
  6. 2026-10-30 5 new references · GHSA-662x-8wvj-2276
  7. 2026-11-03 CISA SSVC decision points changed
  8. 2026-11-03 Priority changed: LOW → MEDIUM
  9. 2026-11-06 Affected versions changed · Red Hat
  10. 2026-11-06 CVSS score added · Red Hat

References

Advisory 1

Other 4

  • TI-2026-65512 russh: Client-side channel-scoped Handler callbacks fire for channel IDs the client never opened CVSS 3.1HIGH 7.5
  • TI-2026-35550 Russh: SSH message fields were decoded through allocation-first parsers before field-specific bounds CVSS 3.1HIGH 7.5
  • TI-2026-34331 Russh: Post-decompression SSH packet size was not bounded, allowing remote oversized compressed packets CVSS 3.1HIGH 7.5
  • TI-2026-34308 Resource allocation without limits in Eugeny russh CVSS 3.1HIGH 7.5
  • TI-2025-16084 Tabby has a TCC Bypass via Misconfigured Node Fuses CVSS 4.0HIGH 8.6
  • TI-2024-36991 Tabby has a TCC Bypass via Unnecessary Permissive Entitlements in Tabby CVSS 4.0HIGH 8.6
See all 25 →

Sources

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