[R-pkg-team] Bug#1034173: r-cran-commonmark: CVE-2023-26485 CVE-2023-24824

[Moritz Mühlenhoff]

Source: r-cran-commonmark
X-Debbugs-CC: team at security.debian.org
Severity: important
Tags: security

Hi,

The following vulnerabilities were published for r-cran-commonmark.

CVE-2023-26485[0]:
| 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)

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

CVE-2023-24824[1]:
| 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 `>` or `-`
| 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.

https://github.com/github/cmark-gfm/security/advisories/GHSA-66g8-4hjf-77xh
https://github.com/github/cmark-gfm/commit/2300c1bd2c8226108885bf019655c4159cf26b59

If you fix the vulnerabilities please also make sure to include the
CVE (Common Vulnerabilities & Exposures) ids in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2023-26485
    https://www.cve.org/CVERecord?id=CVE-2023-26485
[1] https://security-tracker.debian.org/tracker/CVE-2023-24824
    https://www.cve.org/CVERecord?id=CVE-2023-24824

Please adjust the affected versions in the BTS as needed.