CVE-2025-40775

DNS message with invalid TSIG causes an assertion failure

CVE-2025-40775 is fixed in 8 products on 1 platform, first by bind9 1:9.20.0-2ubuntu3.2, released May 21, 2025. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

7.5

Important

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.1531

96th percentile

When an incoming DNS protocol message includes a Transaction Signature(TSIG), BIND always checks it. If the TSIG contains an invalid value inthe algorithm field, BIND immediately aborts with an assertion failure.This issue affects BIND 9 versions 9.20.0 through 9.20.8 and 9.21.0 through9.21.7.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
bind · sles 15.7	9.20.9-150700.3.3.1	SUSE-SU-2025:01787-1	May 30, 2025
bind9 · Debian 13.5 (trixie)	1:9.20.9-1	DEBIAN-CVE-2025-40775	May 21, 2025
bind9 · Debian 14	1:9.20.9-1	DEBIAN-CVE-2025-40775	May 21, 2025
bind9 · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	bind9 1:9.20.0-2ubuntu3.2	May 21, 2025
bind9 · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	bind9 1:9.20.4-3ubuntu1.1	May 21, 2025
bind9-dnsutils · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	bind9-dnsutils 1:9.20.0-2ubuntu3.2	May 21, 2025
bind9-dnsutils · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	bind9-dnsutils 1:9.20.4-3ubuntu1.1	May 21, 2025
bind9-host · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	bind9-host 1:9.20.0-2ubuntu3.2	May 21, 2025
bind9-host · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	bind9-host 1:9.20.4-3ubuntu1.1	May 21, 2025
bind9-libs · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	bind9-libs 1:9.20.0-2ubuntu3.2	May 21, 2025
bind9-libs · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	bind9-libs 1:9.20.4-3ubuntu1.1	May 21, 2025
bind9-utils · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	bind9-utils 1:9.20.0-2ubuntu3.2	May 21, 2025
bind9-utils · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	bind9-utils 1:9.20.4-3ubuntu1.1	May 21, 2025
bind9utils · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	bind9utils 1:9.20.0-2ubuntu3.2	May 21, 2025
bind9utils · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	bind9utils 1:9.20.4-3ubuntu1.1	May 21, 2025
dnsutils · Ubuntu 24.10 (oracular)	1:9.20.0-2ubuntu3.2	dnsutils 1:9.20.0-2ubuntu3.2	May 21, 2025
dnsutils · Ubuntu 25.04 (plucky)	1:9.20.4-3ubuntu1.1	dnsutils 1:9.20.4-3ubuntu1.1	May 21, 2025

Details

Published
May 21, 2025
Weakness
Improper Handling of Undefined Values
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-40775

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