Description
FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains multiple TLS certificate identity validation weaknesses in tls_verify_certificate(), tls_match_hostname(), and x509_utils_get_dns_names(). Because FreeRDP performs custom Common Name and DNS SAN string matching instead of using OpenSSL's length-aware identity validation APIs, it (1) truncates DNS SAN values at embedded NUL bytes (accepting e.g. 'victim.example\0.attacker.example' as 'victim.example'), (2) accepts a matching Common Name even when non-matching DNS SAN entries are present, and (3) accepts IP-literal targets via DNS/CN matching without comparing iPAddress SANs. Under a trusted or misissued certificate chain, an attacker positioned to present such a certificate can bypass server identity verification, weakening TLS server authentication.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| FreeRDP | FreeRDP | < 3.29.0 | 3.29.0 |
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 | freerdp3 | 3.29.0+dfsg-1 | — |
| Debian 13 | freerdp3 | No fix yet | — |
| Debian 12 | freerdp2 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.26.04.1 | — |
| Ubuntu 24.04 LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.24.04.1 | — |
| Ubuntu 22.04 LTS | freerdp2 | No fix yet | — |
| Ubuntu 18.04 LTS | freerdp | No fix yet | — |
| Ubuntu 16.04 LTS | freerdp | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 24.04 LTS | freerdp2 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | freerdp2 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | freerdp2 | No fix yet | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | freerdp +5 | 2:3.6.3-1.amzn2023.0.15 | ALAS2023-2026-2111 |
| Amazon Linux 2 | freerdp +4 | 2:2.11.7-1.amzn2.0.14 | ALAS2-2026-3887 |
Advisories 3
- WID-SEC-2026-2384 FreeRDP: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 28, 2026
- ALAS2-2026-3887 Important: freerdp security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Sep 9, 2026
- ALAS2023-2026-2111 Important: freerdp security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Aug 31, 2026
References
- GitHub Security Advisory (GHSA-43hh-p3vw-hfx3) vendor-advisory
- Patch Commit patch
- VulnCheck Advisory: FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass third-party-advisory