CVE-2026-100229
Description
A flaw was found in GStreamer's H.266 codec parser library (libgstcodecparsers). An out-of-bounds write vulnerability exists in the DCI parsing function, where a reserved field value is incorrectly accepted, causing the parser to write beyond the bounds of an internal structure. An attacker could exploit this by providing a specially crafted H.266 bitstream to a third-party application that uses this library API, potentially causing a crash or memory corruption. No standard GStreamer pipeline element currently invokes the affected code path.
Statement
This vulnerability is rated as Low severity because exploitation requires a third-party application to call the gst_h266_parser_parse_dci() public API with attacker-controlled H.266 DCI data, and no in-tree GStreamer element currently invokes this function. The H.266 parser was introduced in GStreamer 1.26. RHEL 7 (GStreamer 1.x), RHEL 8 (1.16.x), and RHEL 9 (1.22.x) do not contain H.266 support and are not affected.
Mitigation
No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability.
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 | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Red Hat CVSS v3 Score Explanation
Library API; remote bitstream delivery to third-party app calling gst_h266_parser_parse_dci(). No in-tree GStreamer caller. AV/UI under team review.
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 Bruno Fournier for reporting this issue.
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