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CVE Record

CVE-2026-22855: FreeRDP has a heap-buffer-overflow in smartcard_unpack_set_attrib_call

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.

HighCVSS 7.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

FreeRDP versions before 3.20.1 can mishandle inconsistent smartcard attribute data, reading beyond allocated heap memory. A successful attack could expose sensitive process memory or crash the affected process. The issue is rated high severity, but exploitation requires a difficult network-based condition.

Executive priority

Treat as a high-priority patching item for exposed or smartcard-enabled FreeRDP deployments. It is not supported as an emergency active-exploitation event by the supplied evidence. Require prompt inventory and remediation, with faster handling where sensitive process memory or service continuity is important.

Technical view

The smartcard SetAttrib unmarshalling path fails to ensure cbAttrLen matches the available NDR buffer length, causing a heap out-of-bounds read in smartcard_unpack_set_attrib_call. CVSS 3.1 is 7.4: network-accessible, high complexity, no privileges or user interaction, with high confidentiality and availability impact but no stated integrity impact.

Likely exposure

Exposure applies to FreeRDP versions earlier than 3.20.1 where untrusted protocol data can reach the affected smartcard SetAttrib path. The bundle does not establish which configurations enable or exercise that path, so organizations should inventory direct installations and embedded or distribution-supplied FreeRDP packages.

Exploitation context

The supplied record does not identify active exploitation, and the CVE is not listed as KEV in the bundle. Network reachability and no required privileges increase concern, while high attack complexity reduces expected reliability. No exploit code or confirmed attack campaign is cited.

Researcher notes

The documented primitive is an out-of-bounds heap read, not a write. Assessment should focus on NDR length validation and affected-path reachability without assuming code execution. The bundle establishes confidentiality and availability impact but does not provide crash reproducibility, disclosed proof-of-concept status, affected configuration details, or observed exploitation.

Mitigation direction

  • Upgrade upstream FreeRDP to version 3.20.1 or later.
  • For distribution packages, apply the applicable vendor security update rather than relying only on upstream version strings.
  • Prioritize remotely reachable systems and environments using FreeRDP smartcard functionality.
  • Consult FreeRDP and operating-system vendor guidance for any configuration-specific mitigations.

Validation and detection

  • Inventory FreeRDP installations, libraries, containers, and applications that embed the affected code.
  • Confirm upstream installations report version 3.20.1 or later.
  • Verify distribution packages include the vendor's CVE-2026-22855 fix or corresponding erratum.
  • Identify whether smartcard redirection or SetAttrib processing is used in exposed RDP workflows.
  • After updating, rerun approved regression tests for RDP and smartcard operations.
Prepared
Confidence
high
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-125: Exact CWE lookup

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cve · low confidence lookup

CVE-2026-22855 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
19Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.4CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H2.25.2redhat-SADP
5.6CVSS 4.0MediumCVSS: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——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

5.6Medium
CVSS 4.0 vector shape for CVE-2026-22855Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: 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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPfreerdp: FreeRDP heap-buffer-overflow
other:Red Hat severity ratingcvssV3_1
  • 2026-01-14T18:00:47.363Z: Reported to Red Hat.
  • 2026-01-14T17:50:06.209Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
FreeRDPFreeRDP< 3.20.1Listed
Weakness

CWE details

CWE-125

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-125 · source CWE mapping

Out-of-bounds Read

Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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