Affects core cluster infrastructure (Corosync) used widely; unauthenticated DoS and potential memory disclosure.
CVE-2026-35091
Unauthenticated UDP DoS in Corosync (totemudp/totemudpu).
Is CVE-2026-35091 being exploited?
Not confirmed. CVE-2026-35091 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.87% probability of exploitation in the next 30 days.
How severe is CVE-2026-35091?
CVE-2026-35091 is rated High with a CVSS score of 8.2. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-35091?
Yes. A fix has been recorded for CVE-2026-35091. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-35091 affect?
CVE-2026-35091 affects Corosync (totemudp/totemudpu mode). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-35091?
Upgrade to fixed Corosync; if unavailable, disable UDP modes and restrict UDP access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote attacker can cause DoS and potential memory disclosure via out-of-bounds read in Corosync UDP mode.
Immediate action required