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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

CVE-2026-23884 affects FreeRDP clients before 3.21.0. A hostile RDP server can make the client use memory after it was freed, causing a crash and possible heap corruption. The business risk is mainly workstation or jump-host disruption, with code-execution risk noted but not proven in the provided sources.

Executive priority

Treat this as a near-term patching item for systems that use FreeRDP, especially administrator workstations and automation hosts. It is high severity but not shown as actively exploited in the provided evidence.

Technical view

FreeRDP offscreen bitmap deletion can leave `gdi->drawing` referencing freed memory. Later related update packets can dereference that stale pointer, producing a CWE-416 heap-use-after-free. The source bundle rates this CVSS 4.0 7.7 high and says FreeRDP 3.21.0 contains the patch.

Likely exposure

Systems using FreeRDP client versions earlier than 3.21.0 are exposed, especially when connecting to untrusted or attacker-controlled RDP servers. Red Hat advisories indicate downstream package handling, but affected Red Hat product details are not fully provided in the bundle.

Exploitation context

The bundle does not show CISA KEV listing or active exploitation evidence. The stated attack path is a malicious server triggering client-side memory misuse through RDP updates. Sources support crash/DoS impact and potential heap-corruption code-execution risk, but do not prove reliable remote code execution.

Researcher notes

Focus validation on the offscreen bitmap cache deletion path and later drawing-update handling. The key condition is stale `gdi->drawing` state after deletion. Avoid assuming exploitability beyond the advisory’s stated crash, heap corruption, and potential code-execution risk.

Mitigation direction

  • Upgrade FreeRDP to version 3.21.0 or later.
  • Apply applicable Red Hat errata for packaged FreeRDP builds.
  • Avoid connecting FreeRDP clients to untrusted RDP servers.
  • Check vendor guidance for any supported backported fixes.
  • Prioritize jump hosts and administrator workstations first.

Validation and detection

  • Inventory endpoints and images for installed FreeRDP versions.
  • Confirm FreeRDP is 3.21.0 or vendor-fixed equivalent.
  • Review package advisories for Red Hat-managed systems.
  • Check crash telemetry for FreeRDP failures after RDP sessions.
  • Verify remote desktop workflows do not require untrusted server connections.
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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