CVE-2026-22853Public exploitNetwork attack vector

Client memory corruption via unchecked NDR element count

Published Jan 14, 2026 · Updated Jan 14, 2026

Heap buffer overflow in FreeRDP before 3.20.1 allows remote attackers to corrupt client memory via a crafted RDPEAR response. ndr_read_pointedMessageEx allocates an array from hints->count, but ndr_read_uconformant_array accepts a larger on-wire count and writes that many elements. A client user must connect to an attacker-controlled RDP server, after which the overwrite can crash the client or corrupt its process memory.

CVSS severity9.8
Critical
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap buffer overflow in FreeRDP before 3.20.1 allows remote attackers to corrupt client memory via a crafted RDPEAR response. ndr_read_pointedMessageEx allocates an array from hints->count, but ndr_read_uconformant_array accepts a larger on-wire count and writes that many elements. A client user must connect to an attacker-controlled RDP server, after which the overwrite can crash the client or corrupt its process memory.

The record

CVE
CVE-2026-22853
Published
Jan 14, 2026
Updated
Jan 14, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 3.20.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeRDP · FreeRDPversion=< 3.20.1

Published CVSS scores

8.1redhat-SADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8GitHub, Inc.CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo