CVE-2026-35414: 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.

mediumCVSS 4.2CVE-2026-35414

CSIRTS triage

vendor: OpenSSH product: OpenSSH Authentication bypassaffected: before 10.3

What: Mishandling of the authorized_keys principals option with comma characters in certain CA scenarios allows auth bypass.
Who is affected: OpenSSH deployments before version 10.3 using principals lists with Certificate Authorities that include comma characters.
Urgency: Medium priority with a CVSS score of 4.2; requires specific configuration conditions.
Action: Update OpenSSH to version 10.3 or later.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 4.2
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-35414

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-354140.18% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-35414	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[UPDATE] [high] IBM QRadar SIEM: Multiple vulnerabilitiescert-bund
medium[UPDATE] [medium] OpenSSH: Multiple vulnerabilitiescert-bund
unknownUSN-8577-1: OpenSSH vulnerabilityubuntu
unknownPAN-SA-2026-0009 Informational Bulletin: Impact assessment of OSS CVEs in Prisma SD-WAN ION (Severity: INFORMA…paloalto

Recent advisories for OpenSSH

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[NEW] [medium] OpenSSH: Multiple vulnerabilitiescert-bund · 2026-08-20
medium[UPDATE] [medium] OpenSSH: Multiple vulnerabilitiescert-bund · 2026-08-17
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