Description
ARM mbed TLS before 1.3.21 and 2.x before 2.1.9, if optional authentication is configured, allows remote attackers to bypass peer authentication via an X.509 certificate chain with many intermediates. NOTE: although mbed TLS was formerly known as PolarSSL, the releases shipped with the PolarSSL name are not affected.
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 | 2.6.0-1 | — |
| Debian 13 | mbedtls | 2.6.0-1 | — |
| Debian 12 | mbedtls | 2.6.0-1 | — |
| Debian 9 | mbedtls | 2.4.2-1+deb9u1 | DSA-3967-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | mbedtls | 2.2.1-2ubuntu0.2 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 12 | mbedtls | 1.3.19-8.1 | openSUSE-SU-2017:2736-1, openSUSE-SU-2017:2731-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | mbedtls-2 | 2.27.0-1.2 | openSUSE-SU-2024:11043-1 |
| openSUSE Tumbleweed | mbedtls-3 | 3.6.6-1.1 | openSUSE-SU-2026:11119-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | mbedtls +2 | 2.6.0-r0 | — |
| Alpine v3.23 | mbedtls +1 | 2.6.0-r0 | — |
| Alpine v3.22 | mbedtls +1 | 2.6.0-r0 | — |
| Alpine v3.21 | mbedtls +1 | 2.6.0-r0 | — |
| Alpine v3.20 | mbedtls +1 | 2.6.0-r0 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.18 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.17 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.16 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.15 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.14 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.13 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.12 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.11 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.10 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.9 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.8 | mbedtls | 2.6.0-r0 | — |
| Alpine v3.7 | mbedtls | 2.6.0-r0 | — |
Advisories 5
- openSUSE-SU-2026:11119-1 libeverest-3.6.6-1.1 on GA media SUSE / openSUSE Security Updates · Jun 26, 2026
- DSA-3967-1 mbedtls - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:11043-1 libmbedcrypto7-2.27.0-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2017:2736-1 Security update for mbedtls SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2017:2731-1 Security update for mbedtls SUSE / openSUSE Security Updates · Feb 4, 2026
References
- DSA-3967 vendor-advisory
- https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2017-02
- https://github.com/ARMmbed/mbedtls/commit/31458a18788b0cf0b722acda9bb2f2fe13a3fb32
- https://github.com/ARMmbed/mbedtls/commit/d15795acd5074e0b44e71f7ede8bdfe1b48591fc
- https://bugs.debian.org/873557