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Full vulnerability report · 2026
CVE-2026-91947High confidence

FreeRDP Server before 3.31.0 Use-After-Free via DRDYNVC

FreeRDP · FreeRDP

Official source article: GitHub GHSA-6MPX-C8RJ-WHJ5 ↗. Check the applicable product and release in the original source.

7.7HighCVSS 4.0
Recommended action
Patch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.31% 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.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs FreeRDP FreeRDP and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

6 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 2 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

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.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcefreerdp3Affected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 7 Oct 2026
Debian bookwormbookworm · sourcefreerdp2Affected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 7 Oct 2026
Debian forkyforky · sourcefreerdp3Vendor fix publishedDebian records a fixed source-package version for this release.3.31.0+dfsg-1Debian Security Tracker ↗Source updated 7 Oct 2026
Debian sidsid · sourcefreerdp3Vendor fix publishedDebian records a fixed source-package version for this release.3.31.0+dfsg-1Debian Security Tracker ↗Source updated 7 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appsfreerdp2Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 7 Oct 2026
Ubuntu 24.04 LTSnoble · standard archivefreerdp3Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.3.31.0+dfsg-0ubuntu0.24.04.1Canonical Ubuntu Security ↗Source updated 7 Oct 2026
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.

1 current
CVE-2026-91947 · CSAF 2.0 · revision 3 · finalRed Hat Product SecurityFreeRDP: FreeRDP: Use-after-free vulnerability in DRDYNVC parser leads to memory corruption
19 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • 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
Summary
A flaw was found in FreeRDP server. This use-after-free vulnerability exists in the DRDYNVC parser, where a channel pointer is dereferenced after its synchronization lock has been released. An authenticated client can exploit this by racing AUDIN channel closure messages against DRDYNVC data parsing, leading to memory corruption. This could potentially result in arbitrary code execution or a denial of service.
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.

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-2026-78804

No EUVD known-exploited evidence

FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.

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
7.7 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

High technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.

What

FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.

Why

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.

Why

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-362 ↗

CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'). The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRLowPrivileges required: The attacker needs basic user-level 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.
NetworkCWE-362
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-78804Official EUVD mapping

FreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3057FreeRDP: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

Ein Angreifer kann mehrere Schwachstellen in FreeRDP ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.

Official advisory ↗
03

Patch and workaround

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.
Fix availability varies by product
Affected
Fixed
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 15 Sept 2026 · Last source change 16 Sept 2026, 15:41 UTC · CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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 2026-09-16
European sourceENISA EUVD · EUVD-2026-78804
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.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-91947 to remediation: access.redhat.com/CVE-2026-91947.
    Before
    remediation: access.redhat.com/CVE-2026-91947
    After
    remediation: access.redhat.com/CVE-2026-91947
    Red Hat Product Security ↗
  2. Remediation statusRemediation status changed from Mitigation available to Patch available.
    Before
    Mitigation available
    After
    Patch available
    Red Hat Product Security ↗
  3. 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 · Fixed: freerdp-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.10.3-12.el10_2.14.src as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debuginfo-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-debugsource-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-libs-debuginfo-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); freerdp-server-debuginfo-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.10.3-12.el10_2.14.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.10.3-12.el10_2.14.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-2:3.10.3-12.el10_2.14.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); libwinpr-debuginfo-2:3.10.3-12.el10_2.14.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); and 35 more
    Red Hat Product Security ↗
  4. ENISA EUVD mappingEUVD-2026-78804 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-78804"}
    ENISA EUVD ↗
  5. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-78804↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference · GitHub GHSA-6MPX-C8RJ-WHJ5↗Official CVE record (CNA and ADP data)↗NVD record↗
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.
Free version - for non-commercial use only.CVE-2026-91947 · cve.blacktree.nl