Description
An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).
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 | mbedtls | 3.6.6-0.1 | — |
| Debian 13 | mbedtls | 3.6.6-0.1~deb13u1 | — |
| Debian 12 | mbedtls | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | mbedtls | No fix yet | — |
| Ubuntu 26.04 LTS | mbedtls | No fix yet | — |
| Ubuntu 25.10 | mbedtls | No fix yet | — |
| Ubuntu 16.04 LTS | mbedtls | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | mbedtls | No fix yet | — |
| Ubuntu Pro 22.04 LTS | mbedtls | No fix yet | — |
| Ubuntu Pro 20.04 LTS | mbedtls | No fix yet | — |
| Ubuntu Pro 18.04 LTS | mbedtls | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | mbedtls | 3.6.6-1.1 | openSUSE-SU-2026:10498-1 |
Advisories 1
- openSUSE-SU-2026:10498-1 libeverest-3.6.6-1.1 on GA media SUSE / openSUSE Security Updates · Apr 8, 2026