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Fencer Vulns
high 7.5

CVE-2025-40775 in the critical feed json

DNS message with invalid TSIG causes an assertion failure

published 2025-05-21 17 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-16006

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
15.3%
EPSS 15.3% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

When an incoming DNS protocol message includes a Transaction Signature (TSIG), BIND always checks it. If the TSIG contains an invalid value in the 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 through 9.21.7.

Patch / fix

  • isc bind 9.20.9, 9.21.8
  • bind9 Debian 14, Debian 13 1:9.20.9-1

debian advisories DEBIAN-CVE-2025-40775

  • bind SLE Module for Server Applications 15 SP7, SLE Module for Basesystem 15 SP7 9.20.9-150700.3.3.1

suse advisories SUSE-SU-2025:01787-1

  • bind openSUSE Tumbleweed 9.20.9-1.1

opensuse advisories openSUSE-SU-2025:15156-1

  • bind Alpine 3.21, Alpine 3.20, Alpine 3.19 +1 more 9.18.37-r0
  • bind Alpine 3.24, Alpine 3.23, Alpine 3.22 9.20.9-r0

alpine advisories ALPINE-CVE-2025-40775

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • bind Azure Linux 3.0 9.20.9-1

azure linux advisories AZL-61972

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • bind Arch Linux 9.20.9-1

arch linux advisories AVG-2881

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-40775 updated cvss 7.5

bind: DNS message with invalid TSIG causes an assertion failure

  • Red Hat Enterprise Linux 6 bind, bind-sdb, bind-libs, bind-utils, bind-chroot Red Hat Enterprise Linux 7 bind, bind-sdb, bind-libs, bind-utils, bind-chroot, bind-pkcs11, +6 more Red Hat Enterprise Linux 8 bind, bind-sdb, bind9.16, bind-libs, bind-utils, bind-chroot, +14 more Red Hat Enterprise Linux 9 bind, dhcp, bind9.18, bind-libs, bind-utils, dhcp-relay, +11 more Red Hat Enterprise Linux 10 bind Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
17 mo ago

Exploit prediction

15.31% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • ISC BIND 9

Classification

Weakness
  • CWE-232 Improper Handling of Undefined Values

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.