# 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. - Web page: https://patchblox.com/security/cve/CVE-2026-66402 - Priority: Routine - CVSS: n/a (Medium) - EPSS: 0.0034 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Aug 1, 2026 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | freerdp amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | freerdp-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | freerdp-debugsource amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | freerdp-devel amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | freerdp-libs amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | freerdp-libs-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-proxy-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-proxy-modules-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-sdl-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | freerdp-server amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | freerdp-server-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-shadow-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-wayland-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | freerdp3 Debian 14 | 3.29.0+dfsg-1 | [DEBIAN-CVE-2026-66402](https://patchblox.com/security/data/fix/linux/debian-cve-2026-66402.md) | Aug 2, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-proxy-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-proxy-modules-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-sdl-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freerdp3-shadow-x11-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-shadow-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freerdp3-wayland-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-wayland-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freerdp3-x11-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-client3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-client3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-server-proxy3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-server3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-server3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-shadow-subsystem3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-shadow-subsystem3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-shadow3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-shadow3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | libwinpr amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | libwinpr-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | libwinpr-devel amzn 2023 | 2:3.6.3-1.amzn2023.0.15 | [ALAS2023-2026-2111](https://patchblox.com/security/data/fix/linux/alas2023-2026-2111.md) | Aug 31, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwinpr-tools3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libwinpr-tools3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwinpr3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libwinpr3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-winpr-utils-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-noble-winpr3-utils-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 | | Linux | 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](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-winpr3-utils-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. 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