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Fencer Vulns
high 7.5

CVE-2026-55827 json

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

published 2026-07-10 3 mo ago modified 2026-07-15 3 mo ago also EUVD-2026-43004

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

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.

Patch / fix

  • freerdp freerdp 3.27.1
  • freerdp3 Debian 14 3.27.1+dfsg-1

debian advisories DEBIAN-CVE-2026-55827

  • freerdp3 Ubuntu 24.04 LTS 3.30.0+dfsg-0ubuntu0.24.04.1
  • freerdp3 Ubuntu 26.04 LTS 3.30.0+dfsg-0ubuntu0.26.04.1

ubuntu advisories UBUNTU-CVE-2026-55827

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • freerdp RHEL 10.2 2:3.10.3-12.el10_2.7
  • libwinpr RHEL 10.2 2:3.10.3-12.el10_2.7
  • freerdp-libs RHEL 10.2 2:3.10.3-12.el10_2.7
  • freerdp-server RHEL 10.2 2:3.10.3-12.el10_2.7
  • freerdp enterprise linux eus 10.0 2:3.10.3-3.el10_0.10
  • libwinpr enterprise linux eus 10.0 2:3.10.3-3.el10_0.10
  • freerdp-libs enterprise linux eus 10.0 2:3.10.3-3.el10_0.10
  • freerdp-server enterprise linux eus 10.0 2:3.10.3-3.el10_0.10

red hat advisories RHSA-2026:54667RHSA-2026:50747

  • freerdp openSUSE Tumbleweed 3.27.1-1.1

opensuse advisories openSUSE-SU-2026:11065-1

  • freerdp AlmaLinux 10 2:3.10.3-12.el10_2.7
  • libwinpr AlmaLinux 10 2:3.10.3-12.el10_2.7
  • freerdp-libs AlmaLinux 10 2:3.10.3-12.el10_2.7
  • freerdp-server AlmaLinux 10 2:3.10.3-12.el10_2.7

almalinux advisories ALSA-2026:50747

  • freerdp Rocky Linux 10 2:3.10.3-12.el10_2.7

rocky linux advisories RLSA-2026:50747

  • freerdp Alpine 3.24 3.27.1-r0

alpine advisories ALPINE-CVE-2026-55827

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-55827 updated cvss 7.5

FreeRDP: FreeRDP: Remote code execution via heap out-of-bounds write in RemoteFX decoding

  • Red Hat Enterprise Linux 6 freerdp, freerdp-libs, freerdp-plugins Red Hat Enterprise Linux 7 freerdp, libwinpr, freerdp-libs, freerdp-plugins
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 10) freerdp 3.10.3-12.el10_2.7, libwinpr 3.10.3-12.el10_2.7, freerdp-libs 3.10.3-12.el10_2.7
    fixed: vendor fix RHSA-2026:50747
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) freerdp 3.10.3-3.el10_0.10, libwinpr 3.10.3-3.el10_0.10, freerdp-libs 3.10.3-3.el10_0.10
    fixed: vendor fix RHSA-2026:54667
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-server 3.10.3-12.el10_2.7
    fixed: vendor fix RHSA-2026:50747
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) freerdp-server 3.10.3-3.el10_0.10
    fixed: vendor fix RHSA-2026:54667
  • Red Hat Enterprise Linux 8 freerdp, libwinpr, freerdp-libs Red Hat Enterprise Linux 9 freerdp, libwinpr, freerdp-libs
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
3 mo ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-c495-h83v-3prp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • FreeRDP FreeRDP

Classification

Weakness
  • CWE-131 Incorrect Calculation of Buffer Size
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.