PyPi: Pycmarkgfm

CVE-2023-26485

Transitive

Safety vulnerability ID: 54814

This vulnerability was reviewed by experts

The information on this page was manually curated by our Cybersecurity Intelligence Team.

Created at Mar 31, 2023 Updated at Nov 07, 2023
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Advisory

Pycmarkgfm 1.2.0 and prior versions rely on 'cmark-gfm' v0.29.0.gfm.6, which is vulnerable to a polynomial time complexity issue.
https://github.com/zopieux/pycmarkgfm/blob/2c31829e37b9d9be26d442e4a3cc0bbcdc9670a8/generated/cmark-gfm_version.h#L5

Affected package

pycmarkgfm

Latest version: 1.2.1

Bindings to GitHub's Flavored Markdown (cmark-gfm), with enhanced support for task lists.

Affected versions

Fixed versions

Vulnerability changelog

cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. This CVE covers quadratic complexity issues when parsing text which leads with either large numbers of `_` characters. This issue has been addressed in version 0.29.0.gfm.10. Users are advised to upgrade. Users unable to upgrade should validate that their input comes from trusted sources. ### Impact A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. ### Proof of concept ``` $ ~/cmark-gfm$ python3 -c 'pad = "_" * 100000; print(pad + "." + pad, end="")' | time ./build/src/cmark-gfm --to plaintext ``` Increasing the number 10000 in the above commands causes the running time to increase quadratically. ### Patches This vulnerability have been patched in 0.29.0.gfm.10. ### Note on cmark and cmark-gfm XXX: TBD [cmark-gfm](https://github.com/github/cmark-gfm) is a fork of [cmark](https://github.com/commonmark/cmark) that adds the GitHub Flavored Markdown extensions. The two codebases have diverged over time, but share a common core. These bugs affect both `cmark` and `cmark-gfm`. ### Credit We would like to thank @gravypod for reporting this vulnerability. ### References https://en.wikipedia.org/wiki/Time_complexity ### For more information If you have any questions or comments about this advisory: * Open an issue in [github/cmark-gfm](https://github.com/github/cmark-gfm) See CVE-2023-26485.


MISC:https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6ef150987: https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6ef150987
MISC:https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5: https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5

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Severity Details

CVSS Base Score

HIGH 7.5

CVSS v3 Details

HIGH 7.5
Attack Vector (AV)
NETWORK
Attack Complexity (AC)
LOW
Privileges Required (PR)
NONE
User Interaction (UI)
NONE
Scope (S)
UNCHANGED
Confidentiality Impact (C)
NONE
Integrity Impact (I)
NONE
Availability Availability (A)
HIGH