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CVE Record

CVE-2026-23884: Heap-use-after-free in gdi_set_bounds

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, offscreen bitmap deletion leaves `gdi->drawing` pointing to freed memory, causing UAF when related update packets arrive. 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

This is a client-side FreeRDP flaw. A malicious RDP server can make a vulnerable client use memory after it was freed, likely crashing the client and possibly corrupting heap memory. The main business risk is disruption or compromise of systems that use FreeRDP to connect to untrusted or externally controlled RDP servers.

Executive priority

Treat as high priority for teams using FreeRDP clients, especially in administrative workstations, remote support, jump-host, or automation workflows. Patch promptly, but focus first on systems connecting to untrusted RDP servers. Current sources do not justify an emergency active-exploitation response.

Technical view

FreeRDP before 3.21.0 can leave gdi->drawing pointing at freed memory after offscreen bitmap deletion. Later related update packets can trigger a heap use-after-free in gdi_set_bounds. Sources rate it high, CVSS 4.0 score 7.7, CWE-416, with crash impact and possible code-execution risk depending on allocator behavior and heap layout.

Likely exposure

Exposure is most likely on endpoints, jump hosts, tooling, or products using FreeRDP client code below 3.21.0. Risk is higher where users or automation connect to RDP servers not fully controlled by the organization. The bundle does not identify non-FreeRDP affected products beyond downstream vendor packages.

Exploitation context

The provided data does not show CISA KEV listing or confirmed active exploitation. The advisory describes a malicious server triggering the client-side flaw, and the CVSS vector includes proof-of-concept exploit maturity. Do not assume broad exploitation without additional vendor or threat-intelligence confirmation.

Researcher notes

The key primitive is a dangling gdi->drawing pointer after offscreen bitmap deletion, later reached by related update handling. Public sources support DoS and potential heap corruption/code execution risk, but allocator-specific exploitability is not established in the bundle. Validate by version and package lineage rather than by probing live servers.

Mitigation direction

  • Upgrade FreeRDP to version 3.21.0 or later.
  • Apply relevant Red Hat security errata for packaged FreeRDP builds.
  • Restrict FreeRDP use to trusted RDP servers until upgraded.
  • Check vendor guidance for downstream products embedding FreeRDP.
  • Prioritize internet-facing or third-party RDP connection workflows.

Validation and detection

  • Inventory FreeRDP binaries, libraries, containers, and packaged dependencies.
  • Confirm installed FreeRDP versions are 3.21.0 or later.
  • Map systems that connect to untrusted or third-party RDP servers.
  • Review vendor package status against Red Hat advisories where applicable.
  • Check endpoint crash telemetry for abnormal FreeRDP client failures.
Prepared
Confidence
high
Sources
12

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-416: 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-2026-23884 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
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
20Source 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-2026-23884Attack 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: Denial of Service and potential code execution via use-after-free vulnerability
other:Red Hat severity ratingcvssV3_1
  • 2026-01-19T18:01:13.693Z: Reported to Red Hat.
  • 2026-01-19T17:20:40.149Z: 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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