CVE-2026-59846: libssh. A malicious username expanded · OS Command Injection
Affects Red HatSource GCVE Database
Not known to be exploited · CVSS 3.9 Low.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 21 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10libssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8libssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8libssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9libssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9libssh | Affected– | Fixed in– |
| Red Hat Hardened Imageslibssh-main | Affected– | Fixed in– |
AI-suggested
Red Hat has released updated libssh packages (libssh-0.12.1-4.hum1) for Red Hat Hardened Images that address this vulnerability. Users should apply these updates to mitigate the issue. Additionally, ensure that connections are not executed with untrusted username inputs to reduce risk.
Description
A vulnerability in libssh allows a malicious username expanded through %r in ProxyCommand handling to inject shell metacharacters. This can expose environment variables and cause unintended shell behavior. The flaw has a low CVSS score of 3.9 and requires local access with low privileges and user interaction. Red Hat has issued an update for Red Hat Hardened Images RPMs to address this issue.
References
- nvd.nist.gov/vuln/detail/CVE-2026-59846 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:42922 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-59846 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2498179 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:55855 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62217 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:62218 (opens in a new tab)