Out-of-bounds Read in Eugeny Russh
CVE-2026-102820
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.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 6.2 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Eugeny Russh — versions < 0.63.2
- Rust Pageant — versions < 0.2.3
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-102820?
- CVE-2026-102820 is a medium-severity vulnerability in Eugeny Russh, classified under Out-of-bounds Read. CVSS score: 6.2/10. Published 2026-09-29.
- How severe is CVE-2026-102820?
- Medium severity. CVSS v3 base score is 6.2 out of 10.