What’s Vulnerable › Vulnerabilities

CVE-2026-55827: FreeRDP: Heap out-of-bounds write in RemoteFX (RFX) Cache Bitmap V3 decode

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-07-10 · updated 2026-07-15
• Weakness: CWE-131

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.1, FreeRDP clients launched with the non-default /cache:codec:rfx option pass desktop stride and height to RemoteFX decoding for Cache Bitmap V3 data while allocating bitmap->data only for the smaller DstWidth and DstHeight in gdi_Bitmap_Decompress, allowing a malicious RDP server to trigger a heap out-of-bounds write with attacker-controlled offset and content. This issue is fixed in version 3.27.1.

Affected products

• FreeRDP: before 3.27.1 — fixed in 3.27.1

How to fix

Upgrade to a fixed version: FreeRDP 3.27.1. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRDP/FreeRDP/commit/e58adf922ea4c0d5495e59a1fe488d70092e0e3e
• https://github.com/FreeRDP/FreeRDP/pull/12899
• https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.1
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-c495-h83v-3prp
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-c495-h83v-3prp

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