CVE-2025-68142
Description
A flaw was found in PyMdown Extensions. This vulnerability allows a Regular Expression Denial of Service (ReDOS) via a crafted malicious payload in unchecked user content processed by the figure caption extension (pymdownx.blocks.caption).
Statement
This vulnerability is rated Low for Red Hat as it requires processing of unchecked user-provided markdown content with the pymdownx.blocks.caption extension enabled, without proper safeguards like timeouts. Exploitation is limited to applications that explicitly utilize this specific extension and do not implement robust input validation or resource limits.
Mitigation
To mitigate this issue, avoid using the `pymdownx.blocks.caption` extension within PyMdown Extensions when processing untrusted user-provided markdown content. This can be achieved by disabling the extension in the application's configuration or by ensuring that input is properly sanitized and processed with resource limits to prevent excessive processing time.
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 | 5.3 | 5.3 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU)
Attackers can create crafted inputs that intentionally cause the regular expression to use excessive backtracking in a way that causes the CPU consumption to spike.
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