CVE-2026-91955Public exploitNetwork attack vectorHinoki check available

Pre-auth server crash via unchecked desktop dimensions

Published Sep 15, 2026 · Updated Sep 15, 2026

Denial of service in FreeRDP before 3.31.0 allows remote attackers to crash RDP servers through crafted GCC desktop dimensions. gcc_read_client_core_data stores DesktopWidth and DesktopHeight without range checks, and rdp_write_multifragment_update_capability_set divides by derived zero tile counts or evaluates a reachable assertion. Pre-authentication impact applies to default-assert builds using default multifragment settings with TLS or standard RDP security; NLA requires authentication.

CVSS severity5.9
Medium
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in FreeRDP before 3.31.0 allows remote attackers to crash RDP servers through crafted GCC desktop dimensions. gcc_read_client_core_data stores DesktopWidth and DesktopHeight without range checks, and rdp_write_multifragment_update_capability_set divides by derived zero tile counts or evaluates a reachable assertion. Pre-authentication impact applies to default-assert builds using default multifragment settings with TLS or standard RDP security; NLA requires authentication.

The record

CVE
CVE-2026-91955
Published
Sep 15, 2026
Updated
Sep 15, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-369, CWE-617, T1499.004
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

5.9FreeRDP GitHub Security AdvisoryCVSS:3.1/AV:N/AC:H/PR:N/UI:N/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-369Divide By Zero
CWE-617Reachable Assertion
T1499.004Application or System Exploitation

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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