Read the docs
TI-2026-65509 Aliases CVE-2026-102820GHSA-g4mp-vgx3-xrvm

pageant: Out-of-bounds read / oversized allocation in `pageant` MemoryMap::read via a malicious Pageant agent (Windows)

Priority MEDIUM 61CWE-125Published · Updated

Key facts

Attack vector
Local
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-125 and the CVSS impact.

Summary

pageant provides a [PageantStream] type that implements [AsyncRead] and [AsyncWrite] traits and can be used to talk to a running Pageant instance. Prior to pageant 0.2.3, the Windows pageant crate's pageant/src/wmmessage.rs MemoryMap::read function trusts a peer-controlled u32 response length supplied through the 8192-byte Pageant shared-memory mapping reached by AgentClient::connect_pageant. A local process that impersonates the Pageant window can make query_pageant_direct allocate up to approximately 4 GiB and copy beyond the mapped view, reliably crashing a russh client and conditionally exposing adjacent committed memory. This issue is fixed in pageant 0.2.3.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00191 8th percentileScored 2026-11-07
Fix Fixed russh (Eugeny): 0.63.2pageant (rust): 0.2.3+1 more product

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
Eugenyrusshbefore 0.63.20.63.2Patch availableCNA
rustpageantbefore 0.2.30.2.3Patch availableCNA
—pageant (crates.io)before 0.2.30.2.3Patch availableGHSA-g4mp-vgx3-xrvm
  • russh VendorEugeny Affected before 0.63.2 Fixed in 0.63.2 Patch available CNA
  • pageant Vendorrust Affected before 0.2.3 Fixed in 0.2.3 Patch available CNA
  • pageant (crates.io) Vendor— Affected before 0.2.3 Fixed in 0.2.3 Patch available GHSA-g4mp-vgx3-xrvm

Remediation

  • Fix · CNA russh (Eugeny) Fixed in 0.63.2
  • Fix · CNA pageant (rust) Fixed in 0.2.3
  • Fix · GHSA-g4mp-vgx3-xrvm pageant (crates.io) Fixed in 0.2.3 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. 2026-10-02 Threatist record created from CVE-2026-102820
  2. 2026-10-03 Alias added: GHSA-g4mp-vgx3-xrvm

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