CVE-2026-53702
Description
A stack buffer overflow flaw was found in the GStreamer H.265 codec parser library (gst-plugins-bad). When parsing a buffering period SEI message, the parser uses an incorrect loop bound derived from cpb_cnt_minus1[i] (the loop index) instead of the sub-layer 0 CPB count cpb_cnt_minus1[0] from the referenced Sequence Parameter Set. A crafted H.265 video file or stream can cause the parser to write beyond the bounds of stack-allocated CPB delay arrays, resulting in a crash or potential stack memory corruption.
Statement
The upstream maintainer confirmed this flaw causes crashes from crafted H.265 files or streams. Code execution is considered unlikely on Red Hat Enterprise Linux due to standard hardening measures including ASLR and stack protectors. The fix is public in GStreamer 1.28.3 (MR !11334, commit 48c11b7b01).
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base 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 | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | Required | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
Stack buffer overflow in H.265 SEI parser. Confirmed crash from crafted files. Code execution unlikely with ASLR and stack canaries.
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 Tianshuo Han for reporting this issue.
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