CVE-2026-34580
TLS trust validation bypass in Botan 3.11.0; DN/SKI match spoofed root.
Is CVE-2026-34580 being exploited?
Not confirmed. CVE-2026-34580 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 0.25% probability of exploitation in the next 30 days.
How severe is CVE-2026-34580?
CVE-2026-34580 is rated Critical with a CVSS score of 9.3. 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-2026-34580?
Yes. A fix has been recorded for CVE-2026-34580. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-34580 affect?
CVE-2026-34580 affects Botan 3.11.0, Software using Botan for TLS/PKI. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-34580?
Upgrade to Botan 3.11.1+
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
MITM possible: non-identical cert accepted as trusted if DN and SKI match a root.
Patch when possible
- affected>= 3.11.0 and < 3.11.1
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.