CVE-2026-59849: libssh. Logic errors · Infinite Loop
Source GCVE Database
Not known to be exploited · CVSS 3.1 Low.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:LExploitation 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 Hardened Imageslibssh-main | Affected– | Fixed in– |
| Red Hat Enterprise Linux 8libssh | Affected– | Fixed in– |
| Red Hat Enterprise Linux 9libssh | Affected– | Fixed in– |
AI-suggested
Red Hat has released updated libssh packages to fix this vulnerability. Users should apply the security update RHSA-2026:42922 which includes libssh version 0.12.1-4.hum1. Until patched, it is recommended to avoid connecting to untrusted SSH servers and not to use certificate-based authentication. No other mitigations are specified by Red Hat.
Description
A logic flaw in libssh's automatic certificate-based public key authentication can cause clients to enter an infinite loop when configured certificates are missing or repeatedly rejected by a server. This results in a denial of service due to resource exhaustion. The vulnerability has a low severity score and does not impact confidentiality or integrity. A security update is available from Red Hat to address this issue.
References
- nvd.nist.gov/vuln/detail/CVE-2026-59849 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:42922 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-59849 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2498182 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:55855 (opens in a new tab)