CVE-2026-91954Public exploitNetwork attack vectorHinoki check available

Client crash via unchecked NSCodec decoder pointer

Published Sep 15, 2026 · Updated Sep 15, 2026

NULL pointer dereference in FreeRDP before 3.31.0 allows remote attackers controlling an RDP server to crash connected clients. The gdi_surface_bits handler passes an uninitialized NSCodec decoder pointer to nsc_process_message without checking whether the codec was enabled. A user must connect the client to the attacker's server; the default NSCodec-disabled configuration is exposed, and the bounded consequence is client termination.

CVSS severity6.5
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

NULL pointer dereference in FreeRDP before 3.31.0 allows remote attackers controlling an RDP server to crash connected clients. The gdi_surface_bits handler passes an uninitialized NSCodec decoder pointer to nsc_process_message without checking whether the codec was enabled. A user must connect the client to the attacker's server; the default NSCodec-disabled configuration is exposed, and the bounded consequence is client termination.

The record

CVE
CVE-2026-91954
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-617, CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.31.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeRDP · FreeRDPversion=0 <3.31.0

Published CVSS scores

6.5GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-617Reachable Assertion
CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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