CVE-2026-77692 PUBLISHED

Unauthenticated remote crash of named via a single DoH SIG(0) request

Assigner: isc
Reserved: 21.08.2026 Published: 16.09.2026 Updated: 16.09.2026

An attacker can cause named to abort by sending a crafted DNS-over-HTTPS request with a cryptographically invalid SIG(0) record, and then closing the transport connection prematurely. This issue affects BIND 9 versions 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, and 9.20.9-S1 through 9.20.27-S1.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	ISC
Product	BIND 9
Versions	Default: unaffected affected from 9.20.0 to 9.20.27 (incl.) affected from 9.21.0 to 9.21.25 (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, 9.21.26, or 9.20.29-S1.

Credits

ISC would like to thank Vitaly Simonovich for bringing this vulnerability to our attention.

References

Problem Types

CWE-476 NULL Pointer Dereference CWE

Impacts

A successful attack may result in abnormal program termination and a denial-of-service.