Description
libmodbus v3.1.6 was discovered to contain a use-after-free via the ctx->backend pointer. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted message sent to the unit-test-server.
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 | libmodbus | 3.1.6-2.1 | — |
| Debian 13 | libmodbus | 3.1.6-2.1 | — |
| Debian 12 | libmodbus | 3.1.6-2.1 | — |
| Debian 11 | libmodbus | 3.1.6-2+deb11u1 | DLA-4084-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libmodbus | No fix yet | — |
| Ubuntu 26.04 LTS | libmodbus | No fix yet | — |
| Ubuntu 25.10 | libmodbus | No fix yet | — |
| Ubuntu 24.04 LTS | libmodbus | No fix yet | — |
| Ubuntu 22.04 LTS | libmodbus | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | libmodbus | No fix yet | — |
| Ubuntu Pro 18.04 LTS | libmodbus | No fix yet | — |
| Ubuntu Pro 16.04 LTS | libmodbus | No fix yet | — |
| Ubuntu Pro 14.04 LTS | libmodbus | No fix yet | — |
Advisories 1
- DLA-4084-1 libmodbus - security update Debian Security (DSA / DLA) · Mar 9, 2026