# CVE-2021-46837: asterisk: res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Aste...

CVE-2021-46837 is fixed in asterisk on 1 platform by DEBIAN-CVE-2021-46837 (version 1:18.9.0~dfsg+~cs6.10.40431411-1), released August 30, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-46837
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0467
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 30, 2022

## Description

res_pjsip_t38 in Sangoma Asterisk 16.x before 16.16.2, 17.x before 17.9.3, and 18.x before 18.2.2, and Certified Asterisk before 16.8-cert7, allows an attacker to trigger a crash by sending an m=image line and zero port in a response to a T.38 re-invite initiated by Asterisk. This is a re-occurrence of the CVE-2019-15297 symptoms but not for exactly the same reason. The crash occurs because there is an append operation relative to the active topology, but this should instead be a replace operation.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | asterisk Debian 14 | 1:18.9.0~dfsg+~cs6.10.40431411-1 | [DEBIAN-CVE-2021-46837](https://patchblox.com/security/data/fix/linux/debian-cve-2021-46837.md) | Aug 30, 2022 |

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Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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