Description
Mbed TLS before 2.28.10 and 3.x before 3.6.3, in some cases of failed memory allocation or hardware errors, uses uninitialized stack memory to compose the TLS Finished message, potentially leading to authentication bypasses such as replays.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mbed | mbedtls | < 2.28.10, 3.0.0 – < 3.6.3 | 2.28.10 |
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 | 3.6.3-1 | — |
| Debian 13 | mbedtls | 3.6.3-1 | — |
| Debian 12 | mbedtls | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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 | 2.28.8-1ubuntu0.1~esm1 | USN-8123-1 |
| Ubuntu Pro 22.04 LTS | mbedtls | 2.28.0-1ubuntu0.1~esm1 | USN-8123-1 |
| Ubuntu Pro 20.04 LTS | mbedtls | 2.16.4-1ubuntu2+esm1 | USN-8123-1 |
| Ubuntu Pro 18.04 LTS | mbedtls | 2.8.0-1ubuntu0.1~esm1 | USN-8123-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | mbedtls-2 | 2.28.10-1.1 | openSUSE-SU-2025:14928-1 |
| openSUSE Leap 16.0 | mbedtls | 3.6.6-bp160.1.1 | openSUSE-SU-2026:21144-1 |
| openSUSE Leap 16.0 | mbedtls-2 | 2.28.10-bp160.1.1 | openSUSE-SU-2026:21145-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | mbedtls +1 | 3.6.3-r0 | — |
| Alpine v3.24 | mbedtls2 | 2.28.10-r0 | — |
| Alpine v3.23 | mbedtls | 3.6.3-r0 | — |
| Alpine v3.23 | mbedtls2 | 2.28.10-r0 | — |
| Alpine v3.22 | mbedtls | 3.6.3-r0 | — |
| Alpine v3.22 | mbedtls2 | 2.28.10-r0 | — |
| Alpine v3.21 | mbedtls | 3.6.3-r0 | — |
| Alpine v3.21 | mbedtls2 | 2.28.10-r0 | — |
| Alpine v3.20 | mbedtls | 3.6.3-r0 | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | mbedtls | 2.28.10-r0 | — |
| Alpine v3.18 | mbedtls | 2.28.10-r0 | — |
Advisories 4
- openSUSE-SU-2026:21144-1 Security update for mbedtls SUSE / openSUSE Security Updates · Jun 30, 2026
- openSUSE-SU-2026:21145-1 Security update for mbedtls-2 SUSE / openSUSE Security Updates · Jun 30, 2026
- USN-8123-1 mbedtls vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2025:14928-1 libmbedcrypto7-2.28.10-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026