CVE-2026-18393
Description
A flaw was found in FFmpeg. The tdsc_load_cursor() function writes beyond the bounds of a heap-allocated buffer when processing crafted TDSC cursor data. A remote attacker could exploit this by supplying a specially crafted video file, potentially leading to a denial of service or arbitrary code execution.
Statement
The ffmpeg package is not shipped in base Red Hat Enterprise Linux. It is available through EPEL, Red Hat Enterprise Linux AI, and as a bundled dependency in Red Hat OpenShift AI container images. The vulnerable code resides in libavcodec (tdsc.c), which is compiled and shipped in all FFmpeg builds across these products. The TDSC decoder is present since FFmpeg's initial inclusion of the codec in 2015.
Mitigation
Avoid opening untrusted TDSC-encoded video content with vulnerable FFmpeg consumers until a patched version is available.
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 | 5.4 | N/A | 5.4 |
| Attack Vector | Adjacent Network | N/A | Adjacent Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
cve.org: CVSS:3.1/AV:A/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Acknowledgements
Red Hat would like to thank Seung Min Shin (Ajou University) for reporting this issue.
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