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Full vulnerability report · 2026
CVE-2026-22855High confidence

FreeRDP has a heap-buffer-overflow in smartcard_unpack_set_attrib_call

FreeRDP · FreeRDP

5.6MediumCVSS 4.0
Recommended action
Within 7 days

Medium 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 releaseSource packageVendor stateFixed versionEvidence
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 record ↗Source updated 11 Sept 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.3.5.1+dfsg1-0ubuntu1.4Canonical record ↗Source updated 11 Sept 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-2026-22855 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityfreerdp: FreeRDP heap-buffer-overflow
5 known affected

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

  • freerdp as a component of Red Hat Enterprise Linux 6
  • freerdp-devel as a component of Red Hat Enterprise Linux 6
  • freerdp-libs as a component of Red Hat Enterprise Linux 6
  • freerdp-plugins as a component of Red Hat Enterprise Linux 6
  • freerdp.src as a component of Red Hat Enterprise Linux 6
Summary
A heap based buffer overflow has been discovered in FreeRDP. This heap out-of-bounds read occurs in the smartcard SetAttrib path when cbAttrLen does not match the actual NDR buffer length.
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.

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-2026-2672

No EUVD known-exploited evidence

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, a heap out-of-bounds read occurs in the smartcard SetAttrib path when cbAttrLen does not match the actual NDR buffer length. This vulnerability is fixed in 3.20.1.

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
5.6 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Medium 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 3.20.1, a heap out-of-bounds read occurs in the smartcard SetAttrib path when cbAttrLen does not match the actual NDR buffer length. This vulnerability is fixed in 3.20.1.

What

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, a heap out-of-bounds read occurs in the smartcard SetAttrib path when cbAttrLen does not match the actual NDR buffer length. This vulnerability is fixed in 3.20.1.

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 cause the confidentiality, integrity or availability impact described by the vendor.

What

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, a heap out-of-bounds read occurs in the smartcard SetAttrib path when cbAttrLen does not match the actual NDR buffer length. This vulnerability is fixed in 3.20.1.

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 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.
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 Read → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Passive interaction required
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-125 ↗

CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.

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:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N/E:P

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.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.
NetworkUnauthenticatedCWE-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-2026-2672Official EUVD mapping

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, a heap out-of-bounds read occurs in the smartcard SetAttrib path when cbAttrLen does not match the actual NDR buffer length. This vulnerability is fixed in 3.20.1.

Official EUVD record ↗
BSI · German · WID-SEC-2026-0111FreeRDP: Mehrere Schwachstellen

Ein entfernter Angreifer kann mehrere Schwachstellen in FreeRDP ausnutzen,um möglicherweise einen Denial-of-Service-Zustand zu verursachen, beliebigen Code auszuführen, Daten zu manipulieren oder vertrauliche Informationen offenzulegen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260121Security Bulletin 21 Jan 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 21 Jan 2026, published on 21 January 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-001591FreeRDPにおける境界外読み取りに関する脆弱性

FreeRDPはリモートデスクトッププロトコルの無料実装です。バージョン3.20.1より前のバージョンでは、cbAttrLenが実際のNDRバッファ長と一致しない場合に、スマートカードのSetAttribパスでヒープの境界外読み取りが発生する可能性があります。この脆弱性は3.20.1で修正されました。

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.
Patch available
Affected
Fixed
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
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 14 Jan 2026 · Last source change 19 Aug 2026, 12:05 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 2026-08-14
European sourceENISA EUVD · EUVD-2026-2672
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-2672↗Vendor CSAF · Red Hat Product Security↗CISA Vulnrichment SSVC evidence↗Public exploit reference↗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-2026-22855 · cve.blacktree.nl