Description
An issue was discovered in Mbed TLS before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS). The calculations performed by mbedtls_mpi_exp_mod are not limited; thus, supplying overly large parameters could lead to denial of service when generating Diffie-Hellman key pairs.
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 | 2.16.9-0.1 | — |
| Debian 13 | mbedtls | 2.16.9-0.1 | — |
| Debian 12 | mbedtls | 2.16.9-0.1 | — |
| Debian 10 | mbedtls | 2.16.9-0~deb10u1 | DLA-3249-1 |
| Debian 9 | mbedtls | 2.4.2-1+deb9u4 | DLA-2826-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | mbedtls | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | mbedtls | No fix yet | — |
| Ubuntu Pro 18.04 LTS | mbedtls | No fix yet | — |
Advisories 4
- DLA-3249-1 mbedtls - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2826-1 mbedtls - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SSA-756638 SSA-756638: Vulnerabilities in Third-Party Component Mbed TLS of LOGO! CMR Family and SIMATIC RTU 3000 Family Siemens ProductCERT · May 10, 2022
- ICSA-21-257-20 Siemens LOGO! CMR and SIMATIC RTU 3000 CISA ICS & IT advisories · Sep 14, 2021
References
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18
- https://cert-portal.siemens.com/productcert/pdf/ssa-756638.pdf
- [debian-lts-announce] 20211123 [SECURITY] [DLA 2826-1] mbedtls security update mailing-list
- [debian-lts-announce] 20221225 [SECURITY] [DLA 3249-1] mbedtls security update mailing-list