HighCVE-2026-121964

    FreeRDP: Heap-based Buffer Overflow (CVE-2026-121964)

    Published Sources: BSI

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    What is affected, what to do

    FreeRDP before 3.32.2 contains a heap-based buffer overflow in the RD Gateway RPC client, where rpc_client_recv_fragment writes BIND_ACK and ALTER_CONTEXT_RESP fragments into a persistent PDU stream after checking only total capacity rather than remaining capacity from the current stream position. A malicious or compromised RD Gateway can send crafted RPC fragments with manipulated alloc_hint and frag_length values to overwrite client heap memory with attacker-controlled data, causing a crash or potentially arbitrary code execution.

    An exploit is publicly available. 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

    8.7

    Priority

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

    Source: Vendor (CNA), CVSS v4

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: BSI

    0.6 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 47.5

    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
    80.27 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
    PoC (publicly reported)
    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
    8.7 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
    7.5
    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
    8.7
    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
    0.6 %
    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
    47.5
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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: proof of concept · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 4 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-122

    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

    FreeRDP before 3.32.2 contains a heap-based buffer overflow in the RD Gateway RPC client, where rpc_client_recv_fragment writes BIND_ACK and ALTER_CONTEXT_RESP fragments into a persistent PDU stream after checking only total capacity rather than remaining capacity from the current stream position. A malicious or compromised RD Gateway can send crafted RPC fragments with manipulated alloc_hint and frag_length values to overwrite client heap memory with attacker-controlled data, causing a crash or potentially arbitrary code execution.

    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
    • 3.0.0 – < 3.32.2
    • ≤ 3.32.1
    • < 3.32.2
    • 3.32.2
    • —
    • 3.32.2
    freerdpfreerdp
    • 3.0.0 – < 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-122Heap-based Buffer Overflow

      Variant

      A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

      Entry at MITRE CWE-122

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    References & sources

    • github.comGitHub Security Advisory (GHSA-4qq4-qwxq-49m8)Vendor advisory, Exploit, Mitigation, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP 3.0.0 before 3.32.2 Denial of Service via Slow-Path Input EventThird-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.comCertificate identity validation bypass via tls_verify_certificate (GHSA-jq25-3374-4262)pwn-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
    • github.comHeap out-of-bounds write via RDPGFX HashTable_GetKeys (GHSA-m59q-wm7v-mp57)pwn-watch
    • CVE.org (MITRE)CVE-2026-121953pwn-watch
    • NVD (NIST)CVE-2026-121392pwn-watch
    • github.comGitHub Security Advisory (GHSA-xjhw-2r55-m95g)Vendor advisory, Exploit, Mitigation, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Use-After-Free via RDPGFX ResetGraphics RaceThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-f53w-3364-jr35)Vendor advisory, Exploit, Mitigation, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Heap Overflow via RDPGFX CREATE_SURFACE Integer WrapThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-fg78-v8j5-8697)Vendor advisory, Exploit, Mitigation, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Heap Out-of-Bounds Write in Planar CodecThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-qw7w-hhxq-763c)Vendor advisory, Exploit, Mitigation, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Use-After-Free via DRDYNVC Tracker RaceThird-party advisory, Third-party advisory
    • github.comGitHub Security Advisory (GHSA-j536-qc58-pmf8)Vendor advisory, Exploit, Mitigation, Vendor advisory
    • vulncheck.comVulnCheck Advisory: FreeRDP before 3.32.2 Heap Buffer Overflow via Early User Authorization ReadThird-party advisory, Third-party advisory

    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: proof of concept, automatable: yes

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q82v-5wjg-6h57
      SSVC assessmentadded
      —
      {"id":"CVE-2026-121964","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-11-04T18:19:24.938880Z"}

      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-q82v-5wjg-6h57 Types: Exploit, Mitigation, Vendor Advisory
      Reference typeadded
      —
      VulnCheck: https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-buffer-overflow-via-rpc-client-recv-fragment Types: Third Party Advisory

      Source identifier: nvd@nist.gov

    3. ReceivedVulnCheck

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

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

      Weakness type: CWE-122

      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 heap-based buffer overflow in the RD Gateway RPC client, where rpc_client_recv_fragment writes BIND_ACK and ALTER_CONTEXT_RESP fragments into a persistent PDU stream after checking only total capacity rather than remaining capacity from the current stream position. A malicious or compromised RD Gateway can send crafted RPC fragments with manipulated alloc_hint and frag_length values to overwrite client heap memory with attacker-controlled data, causing a crash or potentially arbitrary code execution.
      CVSSadded
      —
      AV:N/AC:L/AT:N/PR:N/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:N/UI:N/S:U/C:N/I:N/A:H
      Weakness type (CWE)added
      —
      CWE-122
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/121xxx/CVE-2026-121964.json">CVE-2026-121964</a>
      Referenceadded
      —
      https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q82v-5wjg-6h57
      Referenceadded
      —
      https://www.vulncheck.com/advisories/freerdp-before-3.32.2-heap-buffer-overflow-via-rpc-client-recv-fragment

      Source identifier: disclosure@vulncheck.com

    Linked CVEs

    Linked CVEs
    HighCVE-2026-121964FreeRDP before 3.32.2 Heap Buffer Overflow via rpc_client_recv_fragment7.5—
    HighCVE-2026-121963FreeRDP before 3.32.2 Use-After-Free via Dynamic rdpsnd Channel Close5.9—
    HighCVE-2026-121962FreeRDP before 3.32.2 Heap Buffer Overflow via Early User Authorization Read8.1—
    HighCVE-2026-121961FreeRDP before 3.32.2 Use-After-Free via DRDYNVC Tracker Race5.9—
    HighCVE-2026-121960FreeRDP before 3.32.2 Unauthenticated Denial of Service via CredSSP TSRequest7.5—
    HighCVE-2026-121959FreeRDP before 3.32.2 Infinite Loop via Truncated WebSocket Frame6.5—
    HighCVE-2026-121958FreeRDP through 3.32.1 Heap Out-of-Bounds Write via RDPGFX HashTable_GetKeys8.8—
    HighCVE-2026-121957FreeRDP before 3.32.2 Use-After-Free via RDPGFX ResetGraphics Race7.5—
    HighCVE-2026-121956FreeRDP before 3.32.2 Double Free in WinPR Kerberos retrieveSomeTgt7.5—
    HighCVE-2026-121955FreeRDP before 3.32.2 Use-After-Free in Smartcard Emulation ReleaseContext7.5—
    HighCVE-2026-121954FreeRDP before 3.32.2 Heap Out-of-Bounds Write in Planar Codec6.5—
    CriticalCVE-2026-121953FreeRDP before 3.32.2 Use-After-Free via rdpgfx Dynamic Virtual Channel Close9.8—
    CriticalCVE-2026-121952FreeRDP before 3.32.2 Proxy Out-of-Bounds Write via Bitmap Cache v2 Capability9.8—
    HighCVE-2026-121951FreeRDP 3.0.0 before 3.32.2 Denial of Service via Slow-Path Input Event7.5—
    HighCVE-2026-121950FreeRDP before 3.32.2 Heap Overflow via RDPGFX CREATE_SURFACE Integer Wrap6.5—
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