Out-of-bounds Read in Isc Bind
CVE-2026-5946
Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data — can cause assertion failures in `named`. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
EPSS: 0.019 (78.0th 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 9.11.0, 9.18.0, 9.20.0
Weakness classification (CWE)
References
- security-officer@isc.org (Patch, patch)
- security-officer@isc.org (Patch, patch)
- security-officer@isc.org (Patch, patch)
- security-officer@isc.org (vendor-advisory, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-5946?
- CVE-2026-5946 is a high-severity vulnerability in Isc Bind, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-05-20.
- How severe is CVE-2026-5946?
- High severity. CVSS v3 base score is 7.5 out of 10.