# 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.

- Web page: https://patchblox.com/security/cve/CVE-2025-40775
- Priority: High
- CVSS: 7.5 (Important)
- EPSS: 0.1531
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 21, 2025
- Weakness: Improper Handling of Undefined Values
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-40775

## Description

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

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bind sles 15.7 | 9.20.9-150700.3.3.1 | [SUSE-SU-2025:01787-1](https://patchblox.com/security/data/fix/linux/suse-su-2025-01787-1.md) | May 30, 2025 |
| Linux | bind9 Debian 13.5 (trixie) | 1:9.20.9-1 | [DEBIAN-CVE-2025-40775](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40775.md) | May 21, 2025 |
| Linux | bind9 Debian 14 | 1:9.20.9-1 | [DEBIAN-CVE-2025-40775](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40775.md) | May 21, 2025 |
| Linux | bind9 Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [bind9 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-bind9-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | bind9 Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [bind9 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-bind9-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |
| Linux | bind9-dnsutils Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [bind9-dnsutils 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-bind9-dnsutils-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | bind9-dnsutils Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [bind9-dnsutils 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-bind9-dnsutils-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |
| Linux | bind9-host Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [bind9-host 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-bind9-host-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | bind9-host Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [bind9-host 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-bind9-host-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |
| Linux | bind9-libs Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [bind9-libs 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-bind9-libs-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | bind9-libs Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [bind9-libs 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-bind9-libs-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |
| Linux | bind9-utils Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [bind9-utils 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-bind9-utils-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | bind9-utils Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [bind9-utils 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-bind9-utils-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |
| Linux | bind9utils Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [bind9utils 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-bind9utils-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | bind9utils Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [bind9utils 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-bind9utils-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |
| Linux | dnsutils Ubuntu 24.10 (oracular) | 1:9.20.0-2ubuntu3.2 | [dnsutils 1:9.20.0-2ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-dnsutils-1-9.20.0-2ubuntu3.2.md) | May 21, 2025 |
| Linux | dnsutils Ubuntu 25.04 (plucky) | 1:9.20.4-3ubuntu1.1 | [dnsutils 1:9.20.4-3ubuntu1.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-dnsutils-1-9.20.4-3ubuntu1.1.md) | May 21, 2025 |

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