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CVE Record

CVE-2026-23883: Heap-use-after-free in update_pointer_new

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, `xf_Pointer_New` frees `cursorPixels` on failure, then `pointer_free` calls `xf_Pointer_Free` and frees it again, triggering ASan UAF. A malicious server can trigger a client‑side use after free, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.

HighCVSS 7.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-23883 affects FreeRDP clients before 3.21.0. A malicious RDP server can make the client mishandle cursor memory, likely crashing the session and potentially corrupting heap memory. The business risk is highest for users or systems that connect FreeRDP clients to untrusted or externally controlled RDP servers.

Executive priority

Treat as high priority for workstation, jump-host, and administrative environments using FreeRDP. Prioritize patching where users connect to third-party, internet-hosted, or otherwise untrusted RDP servers. No confirmed active exploitation is provided in the bundle.

Technical view

The issue is a heap-use-after-free in FreeRDP's X11 pointer handling. On failure, xf_Pointer_New frees cursorPixels, then pointer_free calls xf_Pointer_Free and frees related state again. Sources describe client-side DoS and possible heap corruption, with code-execution risk dependent on allocator behavior and heap layout.

Likely exposure

Exposure is FreeRDP before 3.21.0, especially X11 client use cases connecting to remote RDP servers. Red Hat advisories indicate downstream packaging impact exists, but exact local exposure depends on installed FreeRDP packages and vendor backports.

Exploitation context

The bundle does not show CISA KEV listing or confirmed active exploitation. The attack model is a malicious server triggering the bug in a connecting client. Public sources support crash and heap-corruption risk, but do not prove reliable remote code execution.

Researcher notes

Focus validation on FreeRDP versions before 3.21.0 and X11 pointer paths. The source bundle identifies the double-free/use-after-free flow across xf_Pointer_New, xf_Pointer_Free, and pointer_free. Exploitability beyond denial of service is not established by the cited sources.

Mitigation direction

  • Upgrade FreeRDP to 3.21.0 or a vendor-patched package.
  • Apply relevant Red Hat security advisories where Red Hat packages are used.
  • Avoid connecting vulnerable FreeRDP clients to untrusted RDP servers.
  • Check vendor guidance for backported fixes in packaged versions.

Validation and detection

  • Inventory systems with FreeRDP or xfreerdp installed.
  • Confirm installed versions are 3.21.0 or vendor-patched.
  • Map users and services connecting to untrusted RDP servers.
  • Review crash telemetry for FreeRDP client failures after RDP connection attempts.
Prepared
Confidence
high
Sources
11

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-416: Exact CWE lookup

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cve · low confidence lookup

CVE-2026-23883 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.7 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P

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
16Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical 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
7.7CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P——GitHub_M
7.6CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H2.84.7redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

7.7High
CVSS 4.0 vector shape for CVE-2026-23883Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/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: Arbitrary code execution and denial of service via malicious server
other:Red Hat severity ratingcvssV3_1
  • 2026-01-19T18:01:42.972Z: Reported to Red Hat.
  • 2026-01-19T17:15:55.735Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
FreeRDPFreeRDP< 3.21.0Listed
Weakness

CWE details

CWE-416

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

CWE-416 · source CWE mapping

Use After Free

Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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