CVE-2026-5673
Description
A flaw was found in libtheora. This heap-based out-of-bounds read vulnerability exists within the AVI (Audio Video Interleave) parser, specifically in the avi_parse_input_file() function. A local attacker could exploit this by tricking a user into opening a specially crafted AVI file containing a truncated header sub-chunk. This could lead to a denial-of-service (application crash) or potentially leak sensitive information from the heap.
Statement
Moderate: A heap-based out-of-bounds read flaw in libtheora's AVI parser can lead to a denial-of-service or information leak. Exploitation requires a local attacker to trick a user into opening a specially crafted AVI file.
Mitigation
To mitigate this issue, users should avoid opening untrusted AVI files. Exercise caution when handling AVI files from unknown or suspicious sources.
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 | 5.6 | 7.1 | 5.6 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | None | Low |
| User Interaction | Required | Required | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | High | Low |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
Acknowledgements
Red Hat would like to thank ChenZhengzhe (HangZhouDianZi University) for reporting this issue.
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