CVE-2026-91945
FreeRDP before 3.31.0 Out-of-bounds Read via Smartcard ATR
Description
FreeRDP versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that fail to validate ATR length fields against fixed inline arrays. Authenticated RDP clients can send oversized ATR lengths in PAKID_CORE_DEVICE_IOCOMPLETION responses to trigger reads past stack or heap objects, causing process termination.
INFO
Published Date :
Sept. 15, 2026, 4:17 p.m.
Last Modified :
Sept. 24, 2026, 12:13 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update FreeRDP to version 3.31.0 or later.
- Apply patches if available from the vendor.
- Validate ATR length handling in smartcard decoders.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-91945.
| URL | Resource |
|---|---|
| https://github.com/FreeRDP/FreeRDP/commit/9626564421df72c84f891afdbc0b20bf702f369f | Patch |
| https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q65v-4w7q-hx3r | Exploit Mitigation Patch Vendor Advisory |
| https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-read-via-smartcard-atr | Third Party Advisory |
| https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q65v-4w7q-hx3r | Exploit Mitigation Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-91945 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-2026-91945
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-91945 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-91945 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 24, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* versions from (including) 3.28.0 up to (excluding) 3.31.0 Added Reference Type VulnCheck: https://github.com/FreeRDP/FreeRDP/commit/9626564421df72c84f891afdbc0b20bf702f369f Types: Patch Added Reference Type VulnCheck: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q65v-4w7q-hx3r Types: Exploit, Mitigation, Patch, Vendor Advisory Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-read-via-smartcard-atr Types: Third Party Advisory Added Reference Type CISA-ADP: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q65v-4w7q-hx3r Types: Exploit, Mitigation, Patch, Vendor Advisory -
New CVE Received by [email protected]
Sep. 15, 2026
Action Type Old Value New Value Added Description FreeRDP versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that fail to validate ATR length fields against fixed inline arrays. Authenticated RDP clients can send oversized ATR lengths in PAKID_CORE_DEVICE_IOCOMPLETION responses to trigger reads past stack or heap objects, causing process termination. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/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 Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-125 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/91xxx/CVE-2026-91945.json">CVE-2026-91945</a> Added Reference https://github.com/FreeRDP/FreeRDP/commit/9626564421df72c84f891afdbc0b20bf702f369f Added Reference https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q65v-4w7q-hx3r Added Reference https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-read-via-smartcard-atr -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 15, 2026
Action Type Old Value New Value Added Reference https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q65v-4w7q-hx3r Added SSVC {'id': 'CVE-2026-91945', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-15T15:51:49.870990Z'}