CVE-2026-102820: Eugeny Russh

Medium severity, CVSS 6.2. EPSS: 0.1% chance of exploitation in the next 30 days.

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.

Affected products

• Eugeny Russh: before 0.63.2 (fixed in 0.63.2)
• Rust Pageant: before 0.2.3 (fixed in 0.2.3)

Published 2026-09-29. Last modified 2026-09-30.