CVE-2026-66402

freerdp3: FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains multiple TLS certificate identity validation weaknesses...

CVE-2026-66402 is fixed in 34 products on 1 platform, first by freerdp3-shadow-x11 3.30.0+dfsg-0ubuntu0.24.04.1, released July 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine
CVSS
n/a
Medium
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0034
27th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
freerdp · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-debuginfo · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-debugsource · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-devel · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-libs · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-libs-debuginfo · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-proxy · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp-proxy 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp-proxy-modules · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp-proxy-modules 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp-sdl · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp-sdl 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp-server · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-server-debuginfo · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
freerdp-shadow-x11 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp-shadow-x11 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp-wayland · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp-wayland 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp-x11 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp-x11 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp3 · Debian 14 3.29.0+dfsg-1 DEBIAN-CVE-2026-66402 Aug 2, 2026
freerdp3-proxy · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp3-proxy 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp3-proxy-modules · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp3-proxy-modules 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp3-sdl · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp3-sdl 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp3-shadow-x11 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 freerdp3-shadow-x11 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
freerdp3-shadow-x11 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp3-shadow-x11 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp3-wayland · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 freerdp3-wayland 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
freerdp3-wayland · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp3-wayland 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
freerdp3-x11 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 freerdp3-x11 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
freerdp3-x11 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 freerdp3-x11 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libfreerdp-client3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libfreerdp-client3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libfreerdp-client3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libfreerdp-client3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libfreerdp-server-proxy3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libfreerdp-server-proxy3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libfreerdp-server3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libfreerdp-server3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libfreerdp-server3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libfreerdp-server3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libfreerdp-shadow-subsystem3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libfreerdp-shadow-subsystem3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libfreerdp-shadow-subsystem3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libfreerdp-shadow-subsystem3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libfreerdp-shadow3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libfreerdp-shadow3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libfreerdp-shadow3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libfreerdp-shadow3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libfreerdp3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libfreerdp3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libfreerdp3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libfreerdp3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libwinpr · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
libwinpr-debuginfo · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
libwinpr-devel · amzn 2023 2:3.6.3-1.amzn2023.0.15 ALAS2023-2026-2111 Aug 31, 2026
libwinpr-tools3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libwinpr-tools3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libwinpr-tools3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libwinpr-tools3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
libwinpr3-3 · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 libwinpr3-3 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
libwinpr3-3 · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 libwinpr3-3 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
winpr-utils · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 winpr-utils 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026
winpr3-utils · Ubuntu 24.04.5 LTS (noble) 3.30.0+dfsg-0ubuntu0.24.04.1 winpr3-utils 3.30.0+dfsg-0ubuntu0.24.04.1 Jul 23, 2026
winpr3-utils · Ubuntu 26.04.1 LTS (resolute) 3.30.0+dfsg-0ubuntu0.26.04.1 winpr3-utils 3.30.0+dfsg-0ubuntu0.26.04.1 Nov 7, 2026

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