LiveActive security incident?Get immediate response
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
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-22855 affects FreeRDP before 3.20.1. A malicious or malformed Remote Desktop smartcard message can cause FreeRDP to read outside allocated heap memory. The published impact is high confidentiality and availability risk. The sources state it is fixed in FreeRDP 3.20.1; they do not show active exploitation.

Executive priority

Prioritize remediation for systems that use FreeRDP to connect to untrusted or externally influenced RDP services. This is a high-severity memory safety issue with possible data exposure or service disruption, but current supplied evidence does not show active exploitation.

Technical view

FreeRDP has a CWE-125 heap out-of-bounds read in smartcard_unpack_set_attrib_call. The issue occurs when cbAttrLen does not match the actual NDR buffer length in the smartcard SetAttrib path. CVSS 3.1 is 7.4: network reachable, high attack complexity, no privileges, no user interaction, with confidentiality and availability impact.

Likely exposure

Systems using FreeRDP versions earlier than 3.20.1 are potentially exposed. Exposure is most relevant where FreeRDP clients or packaged FreeRDP components process RDP smartcard traffic. Red Hat has related CVE and errata references, so organizations should check distribution-specific package status rather than relying only on upstream version numbers.

Exploitation context

The CVSS vector indicates remote network attack surface, no required privileges, and no user interaction, but high attack complexity. The provided sources do not include proof of active exploitation, and the CVE is not marked as KEV. Treat exploitation as plausible but not confirmed in the supplied evidence.

Researcher notes

Key details are limited to the advisory description and CVSS data. The vulnerable path is smartcard SetAttrib NDR unpacking with a length mismatch. Avoid assuming affected downstream packages without vendor confirmation. Red Hat references multiple advisories, but distribution-specific fixed versions should be taken from those advisories.

Mitigation direction

  • Upgrade upstream FreeRDP to 3.20.1 or later.
  • Apply applicable vendor or distribution security errata for FreeRDP packages.
  • Check Red Hat advisories if using Red Hat supplied FreeRDP packages.
  • If immediate patching is not possible, follow vendor guidance for temporary risk reduction.

Validation and detection

  • Inventory systems and applications that include FreeRDP.
  • Confirm installed FreeRDP versions are 3.20.1 or vendor-fixed builds.
  • Review package manager advisories for matching Red Hat errata where applicable.
  • Monitor the upstream advisory and vendor CVE pages for status changes.
Prepared
Confidence
high
Sources
5

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-125: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-22855 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
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.

Open CWE intelligenceSame-CWE CVEs