CVE-2026-7598: libssh2 userauth.c userauth_password integer overflow

Severity: high (CVSS 7.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-01 · updated 2026-09-01
Weakness: CWE-189

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.

Affected products

libssh2: through 1.11.1

References

https://github.com/libssh2/libssh2/
https://github.com/libssh2/libssh2/commit/256d04b60d80bf1190e96b0ad1e91b2174d744b1
https://github.com/libssh2/libssh2/pull/1858
https://vuldb.com/submit/805564
https://vuldb.com/vuln/360555
https://vuldb.com/vuln/360555/cti
https://access.redhat.com/errata/RHSA-2026:16736
https://access.redhat.com/errata/RHSA-2026:61752
https://access.redhat.com/errata/RHSA-2026:7021
https://access.redhat.com/security/cve/CVE-2026-7598
https://bugzilla.redhat.com/show_bug.cgi?id=2464597
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-7598.json

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