FreeRDP before 3.32.2 Proxy Out-of-Bounds Write via Bitmap Cache v2 Capability
FreeRDP · FreeRDP
Official source article: GitHub GHSA-XC85-4MQC-XGCX ↗. Check the applicable product and release in the original source.
9.3CriticalCVSS 4.0
Recommended action
Within 72 hours
Critical technical impact with a remotely reachable, unauthenticated path and a public exploit reference; no CISA KEV confirmation is currently recorded.
Published severityCritical→Operational priority:Critical, unchanged from published severity.unchanged
Evidence used
No CISA KEV confirmation is currently recorded.
A structured source references public exploit or proof-of-concept material.
The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
EPSS is 0.50% for the current model date.
Compensating controls
Validate the affected product branch and deploy the verified fixed release.
Restrict the affected network interface to trusted sources where business-safe.
Increase monitoring for the attack path and post-exploitation behaviour described in the report.
Verification
Confirm that the asset runs FreeRDP FreeRDP and falls inside the recorded affected range.
Verify the installed build against the product-specific fixed version after deployment.
Validate exposure, authentication requirements and compensating controls in the actual environment.
Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Direct vendor intelligence
Authoritative vendor CSAF and VEX advisories
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
The vendor explicitly identifies these products or versions as containing the fix.
freerdp-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-2:3.32.2-1.el10_2.src as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debuginfo-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debuginfo-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debuginfo-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debuginfo-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debugsource-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debugsource-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10)
freerdp-debugsource-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10)
Summary
A flaw was found in FreeRDP. An out-of-bounds write vulnerability exists in freerdp-proxy when processing Bitmap Cache v2 capability sets. The proxy accepts a client-declared numCellCaches value below five and later indexes the bitmap cache cell array at fixed positions 0 through 4. A client that connects to the proxy and completes capability exchange can cause heap corruption, disclosure of adjacent heap contents to the backend server, or a crash of the proxy process.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Optional official sources
National CERT insights ?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.
Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.
Recommended actionWithin 72 hours
Critical technical impact with a remotely reachable, unauthenticated path and a public exploit reference; no CISA KEV confirmation is currently recorded.
Patch available
01
What, why and how
FreeRDP before 3.32.2 has an out-of-bounds write in the proxy because rdp_read_bitmap_cache_v2_capability_set rejects only numCellCaches values above 5, yet the bitmap cache v2 cell array is later accessed at fixed indices 0 through 4. A client connecting to the proxy can declare fewer than five cell caches in its Confirm Active, causing heap corruption, heap data leakage to the backend, or a crash.
What
FreeRDP before 3.32.2 has an out-of-bounds write in the proxy because rdp_read_bitmap_cache_v2_capability_set rejects only numCellCaches values above 5, yet the bitmap cache v2 cell array is later accessed at fixed indices 0 through 4. A client connecting to the proxy can declare fewer than five cell caches in its Confirm Active, causing heap corruption, heap data leakage to the backend, or a crash.
Why
A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.
What
FreeRDP before 3.32.2 has an out-of-bounds write in the proxy because rdp_read_bitmap_cache_v2_capability_set rejects only numCellCaches values above 5, yet the bitmap cache v2 cell array is later accessed at fixed indices 0 through 4. A client connecting to the proxy can declare fewer than five cell caches in its Confirm Active, causing heap corruption, heap data leakage to the backend, or a crash.
Why
A bounds error lets data be written beyond the intended memory region, potentially corrupting control data.
How
An attacker operating through a network path may attempt exploitation without authentication or user interaction. 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
A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.
Likely attack path
a network path → Out-of-bounds Write → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
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.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.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-787Public exploit reference
A
Official authority intelligence
Only matched European and national findings are included. Language selectors and unavailable sources are omitted.
BSI · German · WID-SEC-2026-4068FreeRDP: Mehrere Schwachstellen
Ein Angreifer kann mehrere Schwachstellen in FreeRDP ausnutzen, um Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand auszulösen, Daten zu manipulieren und offenzulegen sowie möglicherweise beliebigen Code auszuführen.
Official advisory ↗Cyber Security Agency of Singapore · English · CSA-SB-20261111Security Bulletin 11 Nov 2026
The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 11 Nov 2026, published on 11 November 2026. Open the linked bulletin for the product, severity and reference information published in that issue.
Official advisory ↗CSIRT Italia · Italian · freerdp-disponibili-poc-per-molteplici-vulnerabilitaFreeRDP: disponibili PoC per molteplici vulnerabilità
a possibilità di creare canali dinamici virtuali (DVC) duplicati con lo stesso nome ma con differente ChannelId , causando la sovrascrittura del riferimento alla callback associata al canale e il successivo rilascio della relativa memoria senza l'azzeramento del puntatore. Un attaccante, mediante un server RDP opportunamente predisposto, potrebbe causare la corruzione della memoria del client interessato, determinando l'arresto del processo e l'interruzione della sessione remota oppure, ove sussistano particolari condizioni, consentire l'esecuzione di codice arbitrario nel contesto dell'utente che utilizza il client FreeRDP.
La vulnerabilità CVE-2026-121952 - di tipo "Out-of-Bounds Write" e con score CVSS v3.1 pari a 9.8 - è dovuta a meccanismi di controllo non adeguati del parametro numCellCaches utilizzato dalla funzionalità Bitmap Cache V2 del componente Proxy. Un attaccante, tramite un client RDP opportunamente predisposto, potrebbe provocare condizioni di corruzione della memoria del processo interessato, al fine di causare l'interruzione del servizio, ottenere l'accesso a informazioni presenti in memoria oppure, in scenari particolari, l'esecuzione di codice arbitrario.
La vulnerabilità CVE-2026-121392 - di tipo "Certificate Identity Validation Bypass" e con score CVSS v3.1 pari a 7.4 - è
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.
Affected versionsThe structured affected or fixed version information changed.
Before
freerdp.src as a component of Red Hat Enterprise Linux 10
After
Fixed: freerdp-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.32.2-1.el10_2.src as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.32.2-1.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.32.2-1.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.32.2-1.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-debuginfo-2:3.32.2-1.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); and 100 more
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.