FreeRDP up to 3.27.x RDP Sound Server rdpsnd_main.c rdpsnd_server_recv_formats double free

Summaryinfo

A vulnerability, which was classified as very critical, has been found in FreeRDP up to 3.27.x. This vulnerability affects the function rdpsnd_server_recv_formats of the file channels/rdpsnd/server/rdpsnd_main.c of the component RDP Sound Server. The manipulation leads to double free. This vulnerability is referenced as CVE-2026-63652. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as very critical, has been found in FreeRDP up to 3.27.x. This issue affects the function rdpsnd_server_recv_formats of the file channels/rdpsnd/server/rdpsnd_main.c of the component RDP Sound Server. The manipulation with an unknown input leads to a double free vulnerability. Using CWE to declare the problem leads to CWE-415. The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, rdpsnd_server_recv_formats in channels/rdpsnd/server/rdpsnd_main.c frees context->client_formats on a malformed Client Audio Formats PDU without clearing the owning pointer or num_client_formats. An authenticated RDP client can trigger an error such as a cbSize larger than the remaining record, leave the dangling pointer in the server context, and cause rdpsnd_server_context_free to free the same allocation again at session teardown. This reliably terminates the server and can create allocator-dependent heap corruption. This issue is fixed in version 3.28.0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-63652 since 07/17/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/19/2026).

Upgrading to version 3.28.0 eliminates this vulnerability.

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Productinfo

Type

• Remote Access Software

Name

• FreeRDP

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10
• 3.11
• 3.12
• 3.13
• 3.14
• 3.15
• 3.16
• 3.17
• 3.18
• 3.19
• 3.20
• 3.21
• 3.22
• 3.23
• 3.24
• 3.25
• 3.26
• 3.27

License

• open-source

Website

• Product: https://github.com/FreeRDP/FreeRDP/

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