FreeRDP: Out-of-bounds read in H.264 YUV-to-RGB conversion due to decoder/surface dimension mismatch
FreeRDP · FreeRDP
7.2HighCVSS 4.0
Recommended action
Within 7 days
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Patch available
Distribution package intelligence
Ubuntu vendor package status
Canonical’s release and source-package findings are shown separately from local repository availability.
2 package states
Repository candidate not checked
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
Ubuntu release
Source package
Vendor state
Fixed version
Evidence
Ubuntu 24.04 LTSnoble · esm-apps
freerdp2
Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.
Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
1 current
CVE-2026-55192 · CSAF 2.0 · revision 3 · finalRed Hat Product SecurityFreeRDP: FreeRDP: Out-of-bounds read leads to memory disclosure or client crash
20 known affected
The vendor explicitly identifies these products as affected by this CVE.
freerdp as a component of Red Hat Enterprise Linux 10
freerdp-devel as a component of Red Hat Enterprise Linux 10
freerdp-libs as a component of Red Hat Enterprise Linux 10
freerdp-server as a component of Red Hat Enterprise Linux 10
freerdp.src as a component of Red Hat Enterprise Linux 10
libwinpr as a component of Red Hat Enterprise Linux 10
libwinpr-devel as a component of Red Hat Enterprise Linux 10
freerdp as a component of Red Hat Enterprise Linux 7
freerdp-devel as a component of Red Hat Enterprise Linux 7
freerdp-libs as a component of Red Hat Enterprise Linux 7
freerdp-plugins as a component of Red Hat Enterprise Linux 7
freerdp.src as a component of Red Hat Enterprise Linux 7
Summary
A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can provide a specially crafted H.264 video stream that causes the client's H.264 decoder to read beyond its allocated memory. This out-of-bounds read can lead to the disclosure of sensitive client memory or cause the client application to crash, resulting in a denial of service.
Remediation
To mitigate this vulnerability, disable H.264 graphics acceleration in client connection parameters (e.g., omitting `/gfx:avc420` or `/gfx:avc444` in `xfreerdp`) to force legacy RemoteFX or standard software bitmap rendering.
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.
Official European source
ENISA European Vulnerability Database
Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.
1 current
ENISA EUVD identifier
EUVD-2026-62668
No EUVD known-exploited evidence
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.
EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
7.2 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days
High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.
Patch available
01
What, why and how
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.
What
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may disrupt the affected service.
What
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through a network path may attempt exploitation when the stated preconditions are met. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No confirmed evidence
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material ?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.Reference recorded
CISA Vulnrichment records proof-of-concept exploitation in its SSVC data. BlackTree has not independently executed or validated exploit material.
Likely attack path
a network path → Out-of-bounds Read → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Passive interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness ?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.
AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIPassiveUser interaction: A user must unknowingly interact with the vulnerable system.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VINoneVulnerable-system integrity: No direct loss is represented by this metric.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-125Public exploit reference
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
ENISA EUVD · EUVD-2026-62668Official EUVD mapping
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.
Official EUVD recordBSI · German · WID-SEC-W-2026-1933FreeRDP: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in FreeRDP ausnutzen,um nicht näher spezifizierte Auswirkungen zu verursachen, potenziell beliebigen Code auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand zu verursachen.
Operational remediation based on structured source evidence.
Status ?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
freerdp as a component of Red Hat Enterprise Linux 10; freerdp-devel as a component of Red Hat Enterprise Linux 10; freerdp-libs as a component of Red Hat Enterprise Linux 10; freerdp-server as a component of Red Hat Enterprise Linux 10; freerdp.src as a component of Red Hat Enterprise Linux 10; libwinpr as a component of Red Hat Enterprise Linux 10; libwinpr-devel as a component of Red Hat Enterprise Linux 10; freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
Fixed
3.27.0.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
To mitigate this vulnerability, disable H.264 graphics acceleration in client connection parameters (e.g., omitting `/gfx:avc420` or `/gfx:avc444` in `xfreerdp`) to force legacy RemoteFX or standard software bitmap rendering.
04
Evidence and provenance
Published 19 Aug 2026 · Last source change 25 Aug 2026, 03:36 UTC · CWE-125 · Out-of-bounds Read
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source ?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.FIRST · tracked since 2026-08-23
European sourceENISA EUVD · EUVD-2026-62668
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment
Core structured fields are present and their contributing authorities are shown above.
Affected versionsThe structured affected or fixed version information changed.
Before
freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
After
freerdp as a component of Red Hat Enterprise Linux 10; freerdp-devel as a component of Red Hat Enterprise Linux 10; freerdp-libs as a component of Red Hat Enterprise Linux 10; freerdp-server as a component of Red Hat Enterprise Linux 10; freerdp.src as a component of Red Hat Enterprise Linux 10; libwinpr as a component of Red Hat Enterprise Linux 10; libwinpr-devel as a component of Red Hat Enterprise Linux 10; freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
Affected versionsThe structured affected or fixed version information changed.
Before
freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 8; freerdp-devel as a component of Red Hat Enterprise Linux 8; freerdp-libs as a component of Red Hat Enterprise Linux 8; freerdp.src as a component of Red Hat Enterprise Linux 8; libwinpr as a component of Red Hat Enterprise Linux 8; libwinpr-devel as a component of Red Hat Enterprise Linux 8; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
After
freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
Affected versionsThe structured affected or fixed version information changed.
Before
freerdp as a component of Red Hat Enterprise Linux 10; freerdp-devel as a component of Red Hat Enterprise Linux 10; freerdp-libs as a component of Red Hat Enterprise Linux 10; freerdp-server as a component of Red Hat Enterprise Linux 10; freerdp.src as a component of Red Hat Enterprise Linux 10; libwinpr as a component of Red Hat Enterprise Linux 10; libwinpr-devel as a component of Red Hat Enterprise Linux 10; freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 8; freerdp-devel as a component of Red Hat Enterprise Linux 8; freerdp-libs as a component of Red Hat Enterprise Linux 8; freerdp.src as a component of Red Hat Enterprise Linux 8; libwinpr as a component of Red Hat Enterprise Linux 8; libwinpr-devel as a component of Red Hat Enterprise Linux 8; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
After
freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 8; freerdp-devel as a component of Red Hat Enterprise Linux 8; freerdp-libs as a component of Red Hat Enterprise Linux 8; freerdp.src as a component of Red Hat Enterprise Linux 8; libwinpr as a component of Red Hat Enterprise Linux 8; libwinpr-devel as a component of Red Hat Enterprise Linux 8; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
Affected versionsThe structured affected or fixed version information changed.
Before
freerdp as a component of Red Hat Enterprise Linux 10; freerdp-devel as a component of Red Hat Enterprise Linux 10; freerdp-libs as a component of Red Hat Enterprise Linux 10; freerdp-server as a component of Red Hat Enterprise Linux 10; freerdp.src as a component of Red Hat Enterprise Linux 10; libwinpr as a component of Red Hat Enterprise Linux 10; libwinpr-devel as a component of Red Hat Enterprise Linux 10
After
freerdp as a component of Red Hat Enterprise Linux 10; freerdp-devel as a component of Red Hat Enterprise Linux 10; freerdp-libs as a component of Red Hat Enterprise Linux 10; freerdp-server as a component of Red Hat Enterprise Linux 10; freerdp.src as a component of Red Hat Enterprise Linux 10; libwinpr as a component of Red Hat Enterprise Linux 10; libwinpr-devel as a component of Red Hat Enterprise Linux 10; freerdp as a component of Red Hat Enterprise Linux 7; freerdp-devel as a component of Red Hat Enterprise Linux 7; freerdp-libs as a component of Red Hat Enterprise Linux 7; freerdp-plugins as a component of Red Hat Enterprise Linux 7; freerdp.src as a component of Red Hat Enterprise Linux 7; libwinpr as a component of Red Hat Enterprise Linux 7; libwinpr-devel as a component of Red Hat Enterprise Linux 7; freerdp as a component of Red Hat Enterprise Linux 8; freerdp-devel as a component of Red Hat Enterprise Linux 8; freerdp-libs as a component of Red Hat Enterprise Linux 8; freerdp.src as a component of Red Hat Enterprise Linux 8; libwinpr as a component of Red Hat Enterprise Linux 8; libwinpr-devel as a component of Red Hat Enterprise Linux 8; freerdp as a component of Red Hat Enterprise Linux 9; freerdp-devel as a component of Red Hat Enterprise Linux 9; freerdp-libs as a component of Red Hat Enterprise Linux 9; freerdp.src as a component of Red Hat Enterprise Linux 9; libwinpr as a component of Red Hat Enterprise Linux 9; libwinpr-devel as a component of Red Hat Enterprise Linux 9
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
CVE-2026-55192: FreeRDP: Out-of-bounds read in H.264 YUV-to-RGB conversion due to decoder/surface dimension mismatch | BlackTree
