CVE-2026-94300

HIGH 8.1

Concurrent GSS-TSIG messages corrupt memory

CVSS Score

8.1

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-415 CWE-362
Vendor	isc
Product	bind 9
Published	Oct 21, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

ISC / BIND 9

9.11.0 ≤ 9.18.50 9.20.0 ≤ 9.20.29 9.21.0 ≤ 9.21.26 9.11.3-S1 ≤ 9.18.50-S1 9.20.9-S1 ≤ 9.20.29-S1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

kb.isc.org: https://kb.isc.org/docs/cve-2026-94300 downloads.isc.org: https://downloads.isc.org/isc/bind9/9.20.30 downloads.isc.org: https://downloads.isc.org/isc/bind9/9.21.27

Credits

While this flaw was discovered in internal testing, ISC would like to thank Dave Aitel from OpenAI who independently discovered and responsibly reported the issue to ISC.