CVE-2026-55827: freerdp Memory Corruption

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.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0053

Probability of exploitation

0.41%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-131 CWE-131

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
freerdp	freerdp	< 3.27.1

References

Advisories & Patches

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

Exploits

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-c495-h83v-3prp https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-c495-h83v-3prp

Other References

https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.1

Frequently Asked Questions

What is CVE-2026-55827? +

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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-55827? +

CVE-2026-55827 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0053, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-55827? +

CVE-2026-55827 affects products from freerdp, specifically: freerdp. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-55827? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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