# CVE-2026-37459: An integer underflow in FRRouting (FRR) stable/10.0 to stable/10.6 allows attackers to cause a Denial of Service (DoS) via supplying a crafted BGP UPDATE message.

CVE-2026-37459 is fixed in 7 products on 1 platform, first by frr 10.4.1-3ubuntu1.4, released May 4, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-37459
- Priority: High
- CVSS: 7.5 (Moderate)
- EPSS: 0.0037
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 4, 2026
- Weakness: Uncontrolled Resource Consumption
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-37459

## Description

An integer underflow in FRRouting (FRR) stable/10.0 to stable/10.6 allows attackers to cause a Denial of Service (DoS) via supplying a crafted BGP UPDATE message.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | frr Debian 14 | 10.6.0-2 | [DEBIAN-CVE-2026-37459](https://patchblox.com/security/data/fix/linux/debian-cve-2026-37459.md) | May 15, 2026 |
| Linux | frr RHEL 10 | 10.4.4-1.el10_2 | [RHSA-2026:24347](https://patchblox.com/security/data/fix/linux/rhsa-2026-24347.md) | Jun 24, 2026 |
| Linux | frr Ubuntu 25.10 (questing) | 10.4.1-3ubuntu1.4 | [frr 10.4.1-3ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-frr-10.4.1-3ubuntu1.4.md) | May 4, 2026 |
| Linux | frr Ubuntu 26.04.1 LTS (resolute) | 10.5.1-1ubuntu4.1 | [frr 10.5.1-1ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-frr-10.5.1-1ubuntu4.1.md) | May 4, 2026 |
| Linux | frr almalinux 10 | 10.4.4-1.el10_2 | [ALSA-2026:24347](https://patchblox.com/security/data/fix/linux/alsa-2026-24347.md) | Jun 8, 2026 |
| Linux | frr ol 10 | 0:10.4.4-1.el10_2 | [ELSA-2026-24347](https://patchblox.com/security/data/fix/linux/elsa-2026-24347.md) | Jul 16, 2026 |
| Linux | frr rocky 10 | 0:10.4.4-1.el10_2 | [RLSA-2026:24347](https://patchblox.com/security/data/fix/linux/rlsa-2026-24347.md) | Jun 11, 2026 |
| Linux | frr-pythontools Ubuntu 25.10 (questing) | 10.4.1-3ubuntu1.4 | [frr-pythontools 10.4.1-3ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-frr-pythontools-10.4.1-3ubuntu1.4.md) | May 4, 2026 |
| Linux | frr-pythontools Ubuntu 26.04.1 LTS (resolute) | 10.5.1-1ubuntu4.1 | [frr-pythontools 10.5.1-1ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-frr-pythontools-10.5.1-1ubuntu4.1.md) | May 4, 2026 |
| Linux | frr-rpki-rtrlib Ubuntu 25.10 (questing) | 10.4.1-3ubuntu1.4 | [frr-rpki-rtrlib 10.4.1-3ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-frr-rpki-rtrlib-10.4.1-3ubuntu1.4.md) | May 4, 2026 |
| Linux | frr-rpki-rtrlib Ubuntu 26.04.1 LTS (resolute) | 10.5.1-1ubuntu4.1 | [frr-rpki-rtrlib 10.5.1-1ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-frr-rpki-rtrlib-10.5.1-1ubuntu4.1.md) | May 4, 2026 |
| Linux | frr-selinux almalinux 10 | 10.4.4-1.el10_2 | [ALSA-2026:24347](https://patchblox.com/security/data/fix/linux/alsa-2026-24347.md) | Jun 8, 2026 |
| Linux | frr-selinux ol 10 | 0:10.4.4-1.el10_2 | [ELSA-2026-24347](https://patchblox.com/security/data/fix/linux/elsa-2026-24347.md) | Jul 16, 2026 |
| Linux | frr-snmp Ubuntu 25.10 (questing) | 10.4.1-3ubuntu1.4 | [frr-snmp 10.4.1-3ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-frr-snmp-10.4.1-3ubuntu1.4.md) | May 4, 2026 |
| Linux | frr-snmp Ubuntu 26.04.1 LTS (resolute) | 10.5.1-1ubuntu4.1 | [frr-snmp 10.5.1-1ubuntu4.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-frr-snmp-10.5.1-1ubuntu4.1.md) | May 4, 2026 |
| Linux | frr10 RHEL 9 | 0:10.4.3-3.el9_8 | [RHSA-2026:24370](https://patchblox.com/security/data/fix/linux/rhsa-2026-24370.md) | Jun 24, 2026 |
| Linux | frr10 almalinux 9 | 10.4.3-3.el9_8 | [ALSA-2026:24370](https://patchblox.com/security/data/fix/linux/alsa-2026-24370.md) | Jun 8, 2026 |
| Linux | frr10 ol 9 | 0:10.4.3-3.el9_8 | [ELSA-2026-24370](https://patchblox.com/security/data/fix/linux/elsa-2026-24370.md) | Jun 24, 2026 |
| Linux | frr10 rocky 9 | 0:10.4.3-3.el9_8 | [RLSA-2026:24370](https://patchblox.com/security/data/fix/linux/rlsa-2026-24370.md) | Jun 11, 2026 |
| Linux | frr10-selinux RHEL 9 | 0:10.4.3-3.el9_8 | [RHSA-2026:24370](https://patchblox.com/security/data/fix/linux/rhsa-2026-24370.md) | Jun 24, 2026 |
| Linux | frr10-selinux almalinux 9 | 10.4.3-3.el9_8 | [ALSA-2026:24370](https://patchblox.com/security/data/fix/linux/alsa-2026-24370.md) | Jun 8, 2026 |
| Linux | frr10-selinux ol 9 | 0:10.4.3-3.el9_8 | [ELSA-2026-24370](https://patchblox.com/security/data/fix/linux/elsa-2026-24370.md) | Jun 24, 2026 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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