CVE-2026-23533
published 2026-01-19CVE-2026-23533: FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec…
PriorityP356critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.43%
35.2th percentile
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | freerdp2 | < freerdp3 3.21.0+dfsg-1 (forky) | freerdp3 3.21.0+dfsg-1 (forky) |
| debian | freerdp3 | < freerdp3 3.21.0+dfsg-1 (forky) | freerdp3 3.21.0+dfsg-1 (forky) |
| freerdp | freerdp | < 3.21.0 | 3.21.0 |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv4.07.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
osv7.7HIGH
vendor_ubuntu9.8CRITICAL
vendor_debian7.7HIGH
vendor_redhat7.7HIGH
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Ubuntu
FreeRDP vulnerabilities
vendor_ubuntu·2026-03-18
CVE-2026-25954 FreeRDP vulnerabilities
Title: FreeRDP vulnerabilities
Summary: Several security issues were fixed in FreeRDP.
It was discovered that FreeRDP incorrectly handled certain RDP packets. A
remote attacker could use this issue to cause FreeRDP to crash, resulting
in a denial of service, or possibly execute arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Ubuntu
FreeRDP regression
vendor_ubuntu·2026-02-08·CVSS 9.8
CVE-2026-23533 [CRITICAL] FreeRDP regression
Title: FreeRDP regression
Summary: USN-8004-1 introduced a regression in FreeRDP
USN-8004-1 fixed vulnerabilities in FreeRDP. The update for
CVE-2026-23533 introduced a regression. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Kim Dong Han discovered that FreeRDP did not correctly validate the size of
certain variables, which could cause a buffer overflow. An attacker could
possibly use this issue to cause a denial of service or execute arbitrary
code.
Instructions: After a standard system update you need to restart your session to make all
the necessary changes.
Ubuntu
FreeRDP vulnerabilities
vendor_ubuntu·2026-02-03
CVE-2026-23533 FreeRDP vulnerabilities
Title: FreeRDP vulnerabilities
Summary: Several security issues were fixed in FreeRDP.
Kim Dong Han discovered that FreeRDP did not correctly validate the size of
certain variables, which could cause a buffer overflow. An attacker could
possibly use this issue to cause a denial of service or execute arbitrary
code.
Instructions: After a standard system update you need to restart your session to make all
the necessary changes.
Red Hat
freerdp: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution
vendor_redhat·2026-01-19·CVSS 7.7
CVE-2026-23533 [HIGH] CWE-122 freerdp: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution
freerdp: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
A flaw was found in FreeRDP, a free implementation of the Remote Desktop Protocol. A malicious server can exploit a client-side heap buffer overflow vulnerability in the RDPGFX ClearCodec decode
Debian
CVE-2026-23533: freerdp2 - FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to versio...
vendor_debian·2026·CVSS 7.7
CVE-2026-23533 [HIGH] CVE-2026-23533: freerdp2 - FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to versio...
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
Scope: local
bookworm: open
bullseye: open
VulDB
FreeRDP up to 3.20.x RDPGFX ClearCodec Decode heap-based overflow (EUVD-2026-3315 / Nessus ID 297418)
vuldb·2026-06-11·CVSS 9.8
CVE-2026-23533 [CRITICAL] FreeRDP up to 3.20.x RDPGFX ClearCodec Decode heap-based overflow (EUVD-2026-3315 / Nessus ID 297418)
A vulnerability, which was classified as critical, has been found in FreeRDP up to 3.20.x. Impacted is an unknown function of the component RDPGFX ClearCodec Decode. This manipulation causes heap-based buffer overflow.
This vulnerability is tracked as CVE-2026-23533. The attack is possible to be carried out remotely. No exploit exists.
It is advisable to upgrade the affected component.
OSV
freerdp2 regression
osv·2026-02-08·CVSS 7.7
CVE-2026-23533 [HIGH] freerdp2 regression
freerdp2 regression
USN-8004-1 fixed vulnerabilities in FreeRDP. The update for
CVE-2026-23533 introduced a regression. This update fixes the problem.
We apologize for the inconvenience.
Original advisory details:
Kim Dong Han discovered that FreeRDP did not correctly validate the size of
certain variables, which could cause a buffer overflow. An attacker could
possibly use this issue to cause a denial of service or execute arbitrary
code.
OSV
CVE-2026-23533: FreeRDP is a free implementation of the Remote Desktop Protocol
osv·2026-01-19·CVSS 7.7
CVE-2026-23533 [HIGH] CVE-2026-23533: FreeRDP is a free implementation of the Remote Desktop Protocol
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-23533 freerdp: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution
bugzilla·2026-01-19·CVSS 7.7
CVE-2026-23533 [HIGH] CVE-2026-23533 freerdp: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution
CVE-2026-23533 freerdp: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
Discussion:
This issue has been addressed in the following products:
Red Hat Enterprise Linux 9
Via RHSA-2026:2048 https://access.redhat.com/errata/RHSA-2026:2048
---
This is
Bugzilla
CVE-2026-23533 freerdp2: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution [fedora-42]
bugzilla·2026-01-19·CVSS 7.7
CVE-2026-23533 [HIGH] CVE-2026-23533 freerdp2: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution [fedora-42]
CVE-2026-23533 freerdp2: FreeRDP: Heap buffer overflow leads to denial of service and potential code execution [fedora-42]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
This message is a reminder that Fedora Linux 42 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 42 on 2026-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '42'.
Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a curr
Wiz
CVE-2026-23533 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 7.7
CVE-2026-23533 [HIGH] CVE-2026-23533 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-23533 :
NixOS vulnerability analysis and mitigation
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
Source : NVD
## 7.7
Score
Published January 19, 2026
Severity HIGH
CNA Score 7.7
Affected Technologies
NixOS
Rocky Linux
Has Public Exploit Yes
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Dat
https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L268-L281https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L336https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-32q9-m5qr-9j2vhttps://access.redhat.com/errata/RHSA-2026:2048https://access.redhat.com/errata/RHSA-2026:2081https://access.redhat.com/errata/RHSA-2026:2222https://access.redhat.com/errata/RHSA-2026:2714https://access.redhat.com/errata/RHSA-2026:2736https://access.redhat.com/errata/RHSA-2026:2770https://access.redhat.com/errata/RHSA-2026:2824https://access.redhat.com/errata/RHSA-2026:2952https://access.redhat.com/errata/RHSA-2026:3036https://access.redhat.com/errata/RHSA-2026:3037https://access.redhat.com/errata/RHSA-2026:3038https://access.redhat.com/errata/RHSA-2026:3039https://access.redhat.com/errata/RHSA-2026:3041https://access.redhat.com/security/cve/CVE-2026-23533https://bugzilla.redhat.com/show_bug.cgi?id=2430886https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23533.json
2026-01-19
Published