CVE-2026-94300

Concurrent GSS-TSIG messages corrupt memory

State: Published
Severity: 8.1 High
Published: Oct 21, 2026
Updated: Oct 22, 2026
Reserved: Sep 21, 2026

Description

Replaying GSS-TSIG signed UDP messages can result in memory corruption in "`named`". An attacker who can capture a previously signed UDP message can replay it while the negotiated TSIG key is still valid. By also sending crafted queries to a zone the attacker controls, the attacker may potentially achieve remote code execution. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.29, 9.21.0 through 9.21.26, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.29-S1.

Scores

CVSS	Score	Vector	Source
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	isc

Weaknesses

CWE-415 Double Free
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

Affected Products

Product	Versions
BIND 9ISC	9.11.0 through 9.18.50Affected 9.20.0 through 9.20.29Affected 9.21.0 through 9.21.26Affected 9.11.3-S1 through 9.18.50-S1Affected 9.20.9-S1 through 9.20.29-S1Affected

References

CVE-2026-94300vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.30patch
https://downloads.isc.org/isc/bind9/9.21.27patch

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