CVE-2026-19662 PUBLISHED

qpcache NOQNAME proof use-after-free crashes recursive resolver

Assigner: isc
Reserved: 12.08.2026 Published: 16.09.2026 Updated: 16.09.2026

An attacker may be able to cause a named resolver to abort. The attack requires inducing the victim resolver to send multiple queries for a DNSSEC-signed zone hosted by an authoritative server under the control of the attacker. If the auth responds with a particular sequence of crafted answers, and those answers arrive in a particular order with particular timing, the named resolver will encounter a use-after-free bug, and abort. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 5.9

Product Status

Vendor ISC
Product BIND 9
Versions Default: unaffected
  • affected from 9.11.0 to 9.18.50 (incl.)
  • affected from 9.20.0 to 9.20.27 (incl.)
  • affected from 9.11.3-S1 to 9.18.50-S1 (incl.)
  • affected from 9.20.9-S1 to 9.20.27-S1 (incl.)

Exploits

We are not aware of any active exploits.

Workarounds

No workarounds known.

Solutions

Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.29 or 9.20.29-S1.

Credits

  • ISC would like to thank Samy Medjahed/Ap4sh for bringing this vulnerability to our attention.

References

Problem Types

  • CWE-416 Use After Free CWE

Impacts

  • A successful attack may result in unexpected program exit and a denial-of-service.