What is CVE-2026-5947?

CVE-2026-5947 is a high-severity vulnerability in Isc Bind, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.5/10. Published 2026-05-20.

How severe is CVE-2026-5947?

High severity. CVSS v3 base score is 7.5 out of 10.

Use After Free in Isc Bind

CVE-2026-5947

Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursi…

Vulnerability class: Race Condition

EPSS: 0.000 (13.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Isc Bind
Isc Bind 9 — versions 9.20.0, 9.21.0, 9.20.9-S1

Weakness classification (CWE)

References

security-officer@isc.org (Patch, patch)
security-officer@isc.org (Patch, patch)
security-officer@isc.org (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-5947?: CVE-2026-5947 is a high-severity vulnerability in Isc Bind, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.5/10. Published 2026-05-20.
How severe is CVE-2026-5947?: High severity. CVSS v3 base score is 7.5 out of 10.