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CVE Record

CVE-2026-22853: FreeRDP has a heap-buffer-overflow in ndr_read_uint8Array

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, RDPEAR’s NDR array reader does not perform bounds checking on the on‑wire element count and can write past the heap buffer allocated from hints, causing a heap buffer overflow in ndr_read_uint8Array. This vulnerability is fixed in 3.20.1.

HighCVSS 8.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

FreeRDP before 3.20.1 has a memory corruption flaw in RDPEAR parsing. A specially crafted network message could cause FreeRDP to write outside an allocated heap buffer. The rated impact is high for confidentiality, integrity, and availability, but exploitation is marked high complexity. No provided source indicates active exploitation.

Executive priority

Treat as a high-priority patching item for environments using FreeRDP, especially where exposed to untrusted networks. The business risk is serious because successful exploitation could compromise systems, but available evidence does not show active exploitation. Remediate through vendor-supported updates rather than emergency assumptions.

Technical view

CVE-2026-22853 is a CWE-787 heap-buffer-overflow in ndr_read_uint8Array. RDPEAR’s NDR array reader trusts an on-wire element count without bounds checking against the heap allocation derived from hints. The CVSS 3.1 score is 8.1, vector AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H. Fixed upstream in FreeRDP 3.20.1.

Likely exposure

Exposure is likely where FreeRDP versions earlier than 3.20.1 are installed, packaged, or embedded. Red Hat has published CVE and errata references, so affected environments should check applicable Red Hat advisories. Evidence provided does not identify other downstream products or specific deployment roles.

Exploitation context

The vulnerability is network-reachable according to CVSS and requires no privileges or user interaction, but attack complexity is high. The provided sources do not state that public exploit code exists or that attacks are occurring. The issue could affect confidentiality, integrity, and availability if successfully exploited.

Researcher notes

Key evidence comes from the FreeRDP advisory and release reference, with Red Hat tracking and errata. The core bug is missing bounds validation of an on-wire count before writing an NDR uint8 array. Do not assume exploitability beyond the CVSS context; the advisory indicates high attack complexity.

Mitigation direction

  • Upgrade FreeRDP to version 3.20.1 or later where applicable.
  • Apply relevant Red Hat errata if using affected Red Hat packages.
  • Check vendor guidance for distributions or products embedding FreeRDP.
  • Prioritize internet-exposed or untrusted-network FreeRDP deployments first.

Validation and detection

  • Inventory systems and applications that include FreeRDP.
  • Confirm installed FreeRDP versions are 3.20.1 or later.
  • Review Red Hat CVE and errata applicability for managed systems.
  • Verify vulnerability scanners map findings to CVE-2026-22853 accurately.
Prepared
Confidence
high
Sources
9

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-787: 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.

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cve · low confidence lookup

CVE-2026-22853 mapping review

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

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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
9Source links

SSVC decision data

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

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
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9redhat-SADP
6.8CVSS 4.0MediumCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P——GitHub_M

Vulnerability scoring details

Base CVSS 4.0 score

6.8Medium
CVSS 4.0 vector shape for CVE-2026-22853Attack 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:H/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
  • 2026-01-14T18:01:01.893Z: Reported to Red Hat.
  • 2026-01-14T17:46:50.159Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
FreeRDPFreeRDP< 3.20.1Listed
Weakness

CWE details

CWE-787

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

CWE-787 · source CWE mapping

Out-of-bounds Write

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

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