Github: Security Vulnerabilities
An incorrect comparison vulnerability was identified in GitHub Enterprise Server that allowed commit smuggling by displaying an incorrect diff within the GitHub pull request UI. To do so, an attacker would need write access to the repository. This vulnerability affected GitHub Enterprise Server versions 3.7.0 and above and was fixed in versions 3.7.9, 3.8.2, and 3.9.1. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
4.8
EPSS Score
0.001
Published
2023-07-27
cmark-gfm is an extended version of the C reference implementation of CommonMark, a rationalized version of Markdown syntax with a spec. Three polynomial time complexity issues in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. These vulnerabilities have been patched in 0.29.0.gfm.12.
CVSS Score
6.4
EPSS Score
0.003
Published
2023-07-13
Visual Studio Code GitHub Pull Requests and Issues Extension Remote Code Execution Vulnerability
CVSS Score
7.8
EPSS Score
0.003
Published
2023-07-11
An incorrect comparison vulnerability was identified in GitHub Enterprise Server that allowed commit smuggling by displaying an incorrect diff. To do so, an attacker would need write access to the repository and be able to correctly guess the target branch before it’s created by the code maintainer. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.9 and was fixed in versions 3.4.18, 3.5.15, 3.6.11, 3.7.8, and 3.8.1. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
6.5
EPSS Score
0.001
Published
2023-04-07
An improper authentication vulnerability was identified in GitHub Enterprise Server that allowed an unauthorized actor to modify other users' secret gists by authenticating through an SSH certificate authority. To do so, a user had to know the secret gist's URL. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.9 and was fixed in versions 3.4.18, 3.5.15, 3.6.11, 3.7.8, and 3.8.1. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
7.7
EPSS Score
0.001
Published
2023-04-07
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.
CVSS Score
5.3
EPSS Score
0.003
Published
2023-03-31
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)
CVSS Score
5.3
EPSS Score
0.001
Published
2023-03-31
A path traversal vulnerability was identified in GitHub Enterprise Server that allowed remote code execution when building a GitHub Pages site. To exploit this vulnerability, an attacker would need permission to create and build a GitHub Pages site on the GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to versions 3.8 and was fixed in versions 3.7.7, 3.6.10, 3.5.14, and 3.4.17. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
4.9
EPSS Score
0.006
Published
2023-03-08
An information disclosure vulnerability was identified in GitHub Enterprise Server that allowed private repositories to be added to a GitHub Actions runner group via the API by a user who did not have access to those repositories, resulting in the repository names being shown in the UI. To exploit this vulnerability, an attacker would need access to the GHES instance, permissions to modify GitHub Actions runner groups, and successfully guess the obfuscated ID of private repositories. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.7 and was fixed in versions 3.3.17, 3.4.12, 3.5.9, 3.6.5. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
4.3
EPSS Score
0.001
Published
2023-03-07
A code injection vulnerability was identified in GitHub Enterprise Server that allowed setting arbitrary environment variables from a single environment variable value in GitHub Actions when using a Windows based runner. To exploit this vulnerability, an attacker would need existing permission to control the value of environment variables for use with GitHub Actions. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.8.0 and was fixed in versions 3.4.15, 3.5.12, 3.6.8, 3.7.5. This vulnerability was reported via the GitHub Bug Bounty program.
CVSS Score
4.1
EPSS Score
0.002
Published
2023-03-02