Description
Asterisk is an open source private branch exchange and telephony toolkit. Prior to Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3, an out-of-bounds write in `chan_unistim` `DIALPAGE` digit handling can overflow the `phone_number` field and crash Asterisk when an attacker sends a carefully crafted incoming request packet. The `chan_unistim` module must be loaded and configured with a valid `UNISTIM UDP port` that the attacker can reach. The attacker must register as a configured `phone MAC`, or the deployment must have an equivalent `production/autoprovisioning` path that allows the client to reach the main page. This issue is fixed in Asterisk 20.20.1, 21.12.3, 22.10.1, 23.4.1 and Certified Asterisk 20.7-cert11, 22.8-cert3.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| asterisk | asterisk | < 20.20.1, >= 21.0.0-pre1, < 21.12.3, >= 22.0.0-pre1, < 22.10.1, >= 23.0.0-pre1, < 23.4.1 | — |
| asterisk | certified-asterisk | < 20.7-cert11, >= 22.8-cert1-pre1, < 22.8-cert3 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | asterisk | 1:22.10.1+dfsg+~cs6.17.60671434-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | asterisk | No fix yet | — |
| Ubuntu 26.04 LTS | asterisk | No fix yet | — |
| Ubuntu 24.04 LTS | asterisk | No fix yet | — |
| Ubuntu 22.04 LTS | asterisk | No fix yet | — |
| Ubuntu 20.04 LTS | asterisk | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | asterisk | No fix yet | — |
| Ubuntu Pro 16.04 LTS | asterisk | No fix yet | — |
Advisories 1
- WID-SEC-2026-4205 Asterisk: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 4, 2026
References
- https://github.com/asterisk/asterisk/security/advisories/GHSA-3g56-cgrh-95p5
- https://github.com/asterisk/asterisk/commit/430f423c84e4e32a462d907632b66c9793236e96
- https://github.com/asterisk/asterisk/commit/6da8e10c210d8e014c27c67235252e1dfc794446
- https://github.com/asterisk/asterisk/commit/6f414ec771eaa3318a4b2d28f70fa387196ae283
- https://github.com/asterisk/asterisk/commit/ce6e2233599b76bc30c33b4816b15609c8ddc8b6
- https://github.com/asterisk/asterisk/commit/d803b5370b05f39a6241b2556eb9894b02148e6a
- https://github.com/asterisk/asterisk/commit/fc3a1cb3c386c962bfca8cd9d533d1390d4ad933
- https://github.com/asterisk/asterisk/commit/ff65e4b0867bee12cdcb3a6219b976ee7ee08963
- https://github.com/asterisk/asterisk/releases/tag/20.20.1
- https://github.com/asterisk/asterisk/releases/tag/21.12.3
- https://github.com/asterisk/asterisk/releases/tag/22.10.1
- https://github.com/asterisk/asterisk/releases/tag/23.4.1
- https://github.com/asterisk/asterisk/releases/tag/certified-20.7-cert11
- https://github.com/asterisk/asterisk/releases/tag/certified-22.8-cert3
- https://github.com/asterisk/asterisk/tree/24.0.0-pre1