CVE-2026-11605 Unnecessary validation of DNSSEC signed records
Attackers can cause CPU exhaustion in BIND by sending queries with superfluous DNSSEC signatures, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-11605?
CVE-2026-11605 is a high-severity denial of service vulnerability in ISC BIND 9, published on 22 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The issue is a resource exhaustion vulnerability associated with DNSSEC validation. BIND always validates all RRSIG records in an answer, even if they are not strictly needed. A query to an authoritative server/zone which returns many valid but superfluous RRSIG records causes the validator to waste disproportionate CPU time. This issue affects BIND 9 versions 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, and 9.20.9-S1 through 9.20.24-S1.
Weakness: CWE-408
Which versions are affected by CVE-2026-11605?
Linux distribution packages (7)
bind Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
bind-chroot Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
bind-devel Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
bind-dnssec-utils Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
bind-doc Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
bind-libs Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
bind-utils Red Hat:hummingbird:1 | All versions | 0:9.18.50-22.hum1 |
How do I fix CVE-2026-11605?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-11605 being exploited?
There is no known exploitation of CVE-2026-11605 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-11605, AZL-93126, BELL-CVE-2026-11605, DEBIAN-CVE-2026-11605, ECHO-35b3-e206-4a0c, GHSA-qhh7-j7w3-xfxq and 5 more.