# CVE-2026-102820: rust-russh: pageant provides a [PageantStream] type that implements [AsyncRead] and [AsyncWrite] traits and can be used to talk t...

CVE-2026-102820 is fixed in rust-russh on 1 platform by DEBIAN-CVE-2026-102820 (version 0.64.1-1), released October 16, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-102820
- Priority: Routine
- CVSS: 6.2 (medium)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 29, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | rust-russh Debian 14 | 0.64.1-1 | [DEBIAN-CVE-2026-102820](https://patchblox.com/security/data/fix/linux/debian-cve-2026-102820.md) | Oct 16, 2026 |

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Data as of 2026-11-10T01:44:33Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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