CVE-2026-91945
Description
A flaw was found in FreeRDP. Authenticated RDP clients can exploit an out-of-bounds read vulnerability in smartcard response decoders. This occurs because the decoders fail to validate the length of Answer to Reset (ATR) fields against fixed inline arrays. By sending oversized ATR lengths, an attacker can trigger reads past memory objects, leading to process termination and a denial of service.
Mitigation
To mitigate this issue, disable smartcard redirection when connecting to RDP servers using FreeRDP. This can typically be achieved by using the `--disable-smartcard` command-line option for `xfreerdp` or similar configuration in other FreeRDP-based clients. Disabling smartcard redirection may impact functionality that relies on smartcard authentication or access within the RDP session.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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