HighCVE-2026-121404

    FreeRDP: Uncontrolled Resource Consumption (CVE-2026-121404)

    Published Sources: BSI

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    What is affected, what to do

    A flaw was found in FreeRDP. An authenticated remote attacker can cause a Denial of Service (DoS) by sending zero-length dynamic virtual channel data messages to the shadow server over an established Remote Desktop Protocol (RDP) session.

    Update FreeRDP to version 3.32.2.

    Affected
    • FreeRDP lt *..3.32.2
    Fixed in
    • FreeRDP 3.32.2

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.1

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v4

    6.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: BSI

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 32.5

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    68.44 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.1 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    6.5
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.1
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.4 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    32.5
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 3 November 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-400

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    A flaw was found in FreeRDP. An authenticated remote attacker can cause a Denial of Service (DoS) by sending zero-length dynamic virtual channel data messages to the shadow server over an established Remote Desktop Protocol (RDP) session. Because the server fails to properly consume these empty messages, receiving server threads enter an infinite loop. This behavior exhausts system CPU resources and degrades performance until the client disconnects.

    Source: BSI WID Portal

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    FreeRDPFreeRDP
    • 2.0.0 – < 3.32.2
    • 3.0.0 – < 3.32.2
    • 3.11.0 – < 3.32.2
    • 3.17.0 – < 3.32.2
    • < 3.32.2
    • 3.32.2
    • 3.32.2
    • 3.32.2
    • 3.32.2
    • 3.32.2
    freerdpfreerdp
    • 2.0.0 – < 3.32.2
    • 3.0.0 – < 3.32.2
    • 3.11.0 – < 3.32.2
    • 3.17.0 – < 3.32.2
    • < 3.32.2
    • 3.32.2
    • 3.32.2
    • 3.32.2
    • 3.32.2
    • 3.32.2
    Open SourceFreeRDP
    • < 3.32.2
    • 3.32.2
    From bundled advisories, not CVE-specific (1)

    Product list of a bundled advisory that does not state which product this CVE affects.

    Products from bundled advisories
    Affected versionsFixed in
    freerdpfreerdp
    • < 3.32.2
    • 3.32.2

    Vendors and products

    Weakness classes (CWE)

    • CWE-400Uncontrolled Resource Consumption

      Class

      The product does not properly control the allocation and maintenance of a limited resource.

      Entry at MITRE CWE-400

    References & sources

    • github.comGitHub Security Advisory (GHSA-3hf9-w6hr-hf9j)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Denial of Service via Oversized X.224 Routing TokenThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-x7w3-32ch-x2jq)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Heap Over-Read via WinPR save_png_to_buffer()Third-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-wg7g-gx9g-r96c)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP 2.0.0 before 3.32.2 Out-of-Bounds Read via GSM610/WAV49 DecoderThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-8rjm-m7xg-mg6m)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Denial of Service via RD Gateway extended-auth packetThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-4vh4-3pc3-32p7)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Memory Exhaustion via RD Gateway Packet LengthThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-c426-ppvf-jpfg)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 X11 Client Crash via Zero-Width RDPGFX ResetGraphicsThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-v3q2-qjvf-7rqw)Vendor advisory, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Use-After-Free via dyn-channel-dump ModuleThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-jq25-3374-4262)Vendor advisory, Vendor advisory, pwn-watch
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Certificate Identity Validation Bypass via tls_verify_certificateThird-party advisory, Third-party advisory
    • pwn.watchpwn.watch: FreeRDP 3.32.2 fixes a batch of heap overflows, use-after-frees and a certificate validation bypass (CVE-2026-121392, CVE-2026-121950 to CVE-2026-121964)pwn-watch
    • github.comFreeRDP 3.32.2 release notespwn-watch
    • github.comUse-after-free via rdpgfx dynamic virtual channel close (GHSA-6wqx-rv3q-vcxp)pwn-watch
    • github.comProxy out-of-bounds write via bitmap cache v2 capability (GHSA-xc85-4mqc-xgcx)pwn-watch

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-121404","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-11-03T17:22:41.442755Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Initial analysis by NVDNVD

      Newly listed as affected:
      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Product configurationadded
      —
      OR *cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* versions up to (excluding) 3.32.2
      Reference typeadded
      —
      VulnCheck: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fqcj-rwww-2498 Types: Vendor Advisory
      Reference typeadded
      —
      VulnCheck: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-cpu-exhaustion-via-zero-length-dvc-data Types: Third Party Advisory

      Source identifier: nvd@nist.gov

    3. ReceivedVulnCheck

      CVSS V4.0: AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

      CVSS V3.1: AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

      Weakness type: CWE-400

      Description added or changed

      Show 7 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      FreeRDP before 3.32.2 contains a denial of service vulnerability in the shadow server that allows authenticated RDP clients to spin server threads by sending zero-length drdynvc DATA PDUs. Attackers can send empty DATA messages on opened audin or rdpgfx channels, so that FreeRDP_WTSVirtualChannelRead never consumes them, consuming full CPU cores until disconnect.
      CVSSadded
      —
      AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      CVSSadded
      —
      AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      CWE-400
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/121xxx/CVE-2026-121404.json">CVE-2026-121404</a>
      Referenceadded
      —
      https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-fqcj-rwww-2498
      Referenceadded
      —
      https://www.vulncheck.com/advisories/freerdp-before-3.32.2-shadow-server-cpu-exhaustion-via-zero-length-dvc-data

      Source identifier: disclosure@vulncheck.com

    Linked CVEs

    Linked CVEs
    HighCVE-2026-121412FreeRDP 3.0.0 before 3.32.2 Proxy Memory Exhaustion via DVC Reassembly6.5—
    HighCVE-2026-121409FreeRDP before 3.32.2 Denial of Service via Oversized X.224 Routing Token5.9—
    MediumCVE-2026-121408FreeRDP before 3.32.2 Use-After-Free via USB Redirection Control Channel5.3—
    HighCVE-2026-121407FreeRDP before 3.32.2 Shadow Server Denial of Service via remdesk Channel6.5—
    MediumCVE-2026-121406FreeRDP before 3.32.2 Client Denial of Service via Zero-Output ZGFX Payload4.3—
    MediumCVE-2026-121405FreeRDP before 3.32.2 Memory Exhaustion via Serial RDPDR Device Control4.3—
    HighCVE-2026-121404FreeRDP before 3.32.2 Shadow Server CPU Exhaustion via Zero-Length DVC DATA6.5—
    HighCVE-2026-121402FreeRDP before 3.32.2 X11 Client Crash via Zero-Width RDPGFX ResetGraphics6.5—
    MediumCVE-2026-121401FreeRDP before 3.32.2 Denial of Service via RD Gateway extended-auth packet4.3—
    HighCVE-2026-121400FreeRDP before 3.32.2 CPU Exhaustion via RDG Control Packet6.5—
    MediumCVE-2026-121399FreeRDP before 3.32.2 Memory Exhaustion via RD Gateway Packet Length4.3—
    HighCVE-2026-121398FreeRDP before 3.32.2 Use-After-Free via dyn-channel-dump Module5.9—
    MediumCVE-2026-121397FreeRDP before 3.32.2 Heap Over-Read via WinPR save_png_to_buffer()4.3—
    MediumCVE-2026-121396FreeRDP 3.0.0 before 3.32.2 denial of service via RTS padding assertion4.3—
    HighCVE-2026-121395FreeRDP 3.17.0 before 3.32.2 Denial of Service via RemoteFX Decoder6.5—
    HighCVE-2026-121394FreeRDP before 3.32.2 Denial of Service via RemoteFX RLGR decoder6.5—
    HighCVE-2026-121393FreeRDP 3.0.0 before 3.32.2 Denial of Service via RemoteFX Region Assertion6.5—
    CriticalCVE-2026-121392FreeRDP before 3.32.2 Certificate Identity Validation Bypass via tls_verify_certificate7.4—
    MediumCVE-2026-121391FreeRDP before 3.32.2 File Descriptor Exhaustion via Parallel CREATE4.3—
    MediumCVE-2026-121390FreeRDP before 3.32.2 Null Pointer Crash via ARM Gateway Response4.3—
    HighCVE-2026-121388FreeRDP 3.0.0 before 3.32.2 Uncapped Memory Allocation via DRDYNVC DATA_FIRST6.5—
    MediumCVE-2026-121387FreeRDP 2.0.0 before 3.32.2 Out-of-Bounds Read via GSM610/WAV49 Decoder4.3—
    HighCVE-2026-121386FreeRDP before 3.32.2 Denial of Service via WinPR PNG/JPEG Image Readers7.5—
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