VulnerabilityModified
CVE-2026-3593
A use-after-free vulnerability exists within the DNS-over-HTTPS implementation.
CRITICAL 9.8EPSS 1.54%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.54%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.54% probability · 73th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416, CWE-825
- Affected
- isc/bind
- Source
- security-officer@isc.org
References
- https://downloads.isc.org/isc/bind9/9.20.23Patch
- https://downloads.isc.org/isc/bind9/9.21.22Patch
- https://kb.isc.org/docs/cve-2026-3593Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:7412
- https://access.redhat.com/security/cve/CVE-2026-3593
- https://bugzilla.redhat.com/show_bug.cgi?id=2479770
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3593.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.