Update dependency pymdown-extensions to v10.16.1 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
pymdown-extensions	10.14.3 → 10.16.1

GitHub Vulnerability Alerts

CVE-2025-68142

Impact

This issue describes a ReDOS bug found within the figure caption extension (pymdownx.blocks.caption ).

In systems that take unchecked user content, this could cause long hangs when processing the data if a malicious payload was crafted.

Patches

This issue is patched in Release 10.16.1.

Workarounds

Some possible workarounds

If users are concerned about this vulnerability and process unknown user content without timeouts or other safeguards in place to prevent really large, malicious content being aimed at systems, the use of pymdownx.blocks.caption could be avoided until the library is updated to 10.16.1+.

References

The original issue https://github.com/facelessuser/pymdown-extensions/issues/2716.

Description

The original issue came through PyMdown Extensions' normal issue tracker instead of the typical security flow: https://github.com/facelessuser/pymdown-extensions/issues/2716. Because this came through the normal issue flow, it was handled as a normal issue. In the future, PyMdown Extensions will ensure such issues, even if prematurely made public through the normal issue flow, are redirected through the typical security process.

The regular expression pattern in question is as follows:

RE_FIG_NUM = re.compile(r'^(\^)?([1-9][0-9]*(?:.[1-9][0-9]*)*)(?= |$)')

The POC was provided by @​ShangzhiXu

import re
import time

regex_pattern = re.compile(r'^(\^)?([1-9][0-9]*(?:.[1-9][0-9]*)*)(?= |$)')

for i in range(50, 500, 50):
    long_string = '1' * i + 'a'
    start_time = time.time()
    match = re.match(regex_pattern, long_string)
    end_time = time.time()
    print(f"long_string execution time: {end_time - start_time:.6f} s")

The issue with the above pattern is that . was used, which accepts any character when we meant to use \.. The fix was to update the pattern to:

RE_FIG_NUM = re.compile(r'^(\^)?([1-9][0-9]*(?:\.[1-9][0-9]*)*)(?= |$)')

Relevant PR with fix: https://github.com/facelessuser/pymdown-extensions/pull/2717

Version(s) & System Info

• Operating System: Any
• Python Version: Any

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Release Notes

facelessuser/pymdown-extensions (pymdown-extensions)

v10.16.1: 10.6.1

Compare Source

10.16.1

• FIX: Inefficient regular expression pattern for figure caption numbers.

v10.16

Compare Source

10.16

• NEW: Add early support for Python 3.14.
• NEW: Drop support for Python 3.8.
• NEW: Snippets: Added max_retries and backoff_retries options to configure new retry logic for HTTP 429
  errors (Too Many Requests client error).
• NEW: Caption: Prefix templates are now preserved exactly as specified allowing the insertion of HTML tags if
  desired.
• FIX: Caption: Fix issue where manual numbers in auto were not respected appropriately.

v10.15

Compare Source

10.15.0

• NEW: SuperFences: Add relaxed_headers option which can tolerate bad content in the fenced code header. When
  enabled, code blocks with bad content in the header will likely still convert into code blocks, often respecting
  the specified language.
• NEW: Add type hints to the Blocks interface and a few additional files.
• FIX: Blocks: Fix some corner cases of nested blocks with lists.
• FIX: Tab and Tabbed: Fix a case where tabs could fail if combine_header_slug was enabled and there was no
  header.

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Configuration

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[github-actions]

Dependency Review

The following issues were found:

• ✅ 0 vulnerable package(s)
• ✅ 0 package(s) with incompatible licenses
• ✅ 0 package(s) with invalid SPDX license definitions
• ⚠️ 1 package(s) with unknown licenses.

See the Details below.

Snapshot Warnings

⚠️: No snapshots were found for the head SHA ca4021a.

Ensure that dependencies are being submitted on PR branches and consider enabling retry-on-snapshot-warnings. See the documentation for more information and troubleshooting advice.

License Issues

uv.lock

Package	Version	License	Issue Type
pymdown-extensions	10.21.2	Null	Unknown License

OpenSSF Scorecard

Package	Version	Score	Details
pip/pymdown-extensions	10.21.2	Unknown	Unknown

Scanned Files

• uv.lock