OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list
Affects opensshSource GCVE Database
Not known to be exploited · CVSS 4.2 Medium · fixed in 1:6.6p1-2ubuntu2.13+esm4 : update openssh when convenient.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1:6.6p1-2ubuntu2.13+esm4, 1:7.2p2-4ubuntu2.10+esm9, 1:7.6p1-4ubuntu0.7+esm6 +5
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 2 Apr 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10openssh-ssh1pkg:deb/ubuntu/openssh-ssh1?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSopensshpkg:deb/ubuntu/openssh?arch=source&distro=resoluteOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSopenssh-ssh1pkg:deb/ubuntu/openssh-ssh1?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10opensshpkg:deb/ubuntu/openssh?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10openssh-ssh1pkg:deb/ubuntu/openssh-ssh1?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSopensshpkg:deb/ubuntu/openssh?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until then, avoid using principals lists with Certificate Authorities that use comma characters in the authorized_keys configuration in affected versions.
Description
OpenSSH versions prior to 10.3 contain a vulnerability in the handling of the authorized_keys principals option. This issue arises in uncommon scenarios where a principals list is used together with a Certificate Authority that utilizes comma characters in a specific way. The vulnerability affects multiple Ubuntu releases and their Pro/FIPS variants. The CVSS vector indicates a network attack vector with high attack complexity and low privileges required, resulting in limited confidentiality and integrity impact without availability impact.
References
- ubuntu.com/security/CVE-2026-35414 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-35414 (opens in a new tab)
- openssh.org/releasenotes.html (opens in a new tab)
- ubuntu.com/security/notices/USN-8222-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8577-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8804-1 (opens in a new tab)