What’s Vulnerable › Vulnerabilities

CVE-2026-63652: FreeRDP: Double-free of `client_formats` in the rdpsnd server channel on a malformed Client Audio Formats PDU

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-08-19 · updated 2026-10-26
• Weakness: CWE-415

Description

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.

Affected products

• FreeRDP: before 3.28.0 — fixed in 3.28.0

How to fix

Upgrade to a fixed version: FreeRDP 3.28.0. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRDP/FreeRDP/commit/caf653c0ba1c75ec8f298d1baa59770102a5d14c
• https://github.com/FreeRDP/FreeRDP/pull/12993
• https://github.com/FreeRDP/FreeRDP/releases/tag/3.28.0
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9g22-w2gr-vcmp
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9g22-w2gr-vcmp

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