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CVE-2026-121958Proof of concept (PoC) published · CISA

FreeRDP through 3.32.1 Heap Out-of-Bounds Write via RDPGFX HashTable_GetKeys

CVSS score

8.7

EPSS probability

—

Risk score

0.9

Published

3 h ago

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

DayBreach AI Explanation

Verified against sources

FreeRDP CVE-2026-121958 RDPGFX Vulnerability

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

FreeRDP through version 3.32.1 contains a heap out-of-bounds write vulnerability in the RDPGFX client [S0]. This is caused by the delete_surface callback truncating surface hash keys to 16 bits [S0].

Why does it matter?

A malicious or man-in-the-middle RDP server can exploit this flaw to trigger severe impacts [S0]. The patch status remains unconfirmed in the reviewed sources [S0].

What should be done?

  • Monitor official vendor advisories [S0].
  • Apply FreeRDP updates when fixes become available [S0].
Chain of evidence and sources2 verified claims

FreeRDP sürüm 3.32.1 ve öncesi, RDPGFX istemcisinde bellek sınırları dışına yazma zafiyeti içermektedir.

Zafiyet, delete_surface geri çağırımının yüzey hash anahtarlarını 16 bite kısaltması nedeniyle yüzey tablosunun tutarsız kalmasından kaynaklanır.

Show the technical text from the sources

FreeRDP through 3.32.1 has a heap out-of-bounds write in the RDPGFX client because the delete_surface callback truncates surface hash keys to 16 bits, leaving the surface table inconsistent so HashTable_GetKeys writes past its allocated key array. A malicious or man-in-the-middle RDP server can exploit this by creating surfaceId 0xFFFF, closing the RDPGFX channel, sending repeated DELETESURFACE PDUs, and then sending ENDFRAME or RESETGRAPHICS.

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

CWE: CWE-122

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-121958 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1freerdpfreerdp View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
8.8CVSS V3_1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCVE CNA
8.8CVSS V31HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HNVD
8.7CVSS V4_0HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE CNA
8.7CVSS V40HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/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:XNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-121958 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-121958 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
User—

Official Sources and Advisories

CVSS Vector Radar Chart

8.7 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.RequiredConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionP
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)P
Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

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Weakness Type (CWE & CAPEC)

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CVE-2026-121958 · FreeRDP through 3.32.1 Heap Out-of-Bounds…