OpenSSH: Always-Incorrect Control Flow Implementation
CVE-2026-35414 is a high-severity always-incorrect control flow implementation vulnerability in OpenSSH from OpenBSD, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 10.3 as the first without the flaw, so updating OpenSSH to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.22% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update OpenSSH to 10.3 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 4.2 | Medium | CNA (mitre.org) |
| CVSS 3.1 | 8.1 | High | NVD |
Official description
OpenSSH before 10.3 mishandles the authorized_keys principals option in uncommon scenarios involving a principals list in conjunction with a Certificate Authority that makes certain use of comma characters.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Always-Incorrect Control Flow Implementation
The code contains a control flow path that does not reflect the algorithm that the path is intended to implement, leading to incorrect behavior any time this path is navigated.
More Always-Incorrect Control Flow Implementation vulnerabilities (CWE-670)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- openssh.org/releasenotes.html#10.3p1Release Notes
Third-party and government advisories
- marc.info/?l=openssh-unix-dev&m=177513443901484&w=2Mailing List, Third Party Advisory
- openwall.com/lists/oss-security/2026/04/02/3Third Party Advisory
Other vulnerabilities in OpenSSH
- 8.1 High severity
- 9.4 Critical severity
- 7.5 High severity
- 8.1 High severity
- 8.1 High severity
- 7.5 High severity
Recent Always-Incorrect Control Flow Implementation vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 8.2 High severity
Spotted an error? Tell us.