GHSA-m64x-33q8-m5h7

GitPython parse_actor_and_date() is vulnerable to quadratic backtracking on malformed identity lines

Published

2026-10-27

Modified

2026-10-27

Sources

github-advisory

Summary

### Summary This is a residual of GHSA-g5vv-9gxw-82hx / CVE-2026-87819. The 3.1.60 fix made `Actor._from_string` regex-free, but `parse_actor_and_date` still runs `_re_actor_epoch` on the same author/committer/tagger line one step earlier. That pattern backtracks quadratically when the trailing epoch or timezone is missing or malformed, so the same class of slow parse is still reachable in 3.1.62. ### Details `git/objects/util.py:322`: ```python _re_actor_epoch = re.compile(r"^.+? (.*) (\d+) ([+-]\d+).*$") ``` `.+?` and `(.*)` can both absorb the same run of spaces, and the required ` (\d+) ([+-]\d+)` tail is only checked after them. On a long line with no valid tail, the search retries every split point. It is called from `parse_actor_and_date` (`git/objects/util.py:335`), which runs on the author and committer lines in `Commit._deserialize` (`git/objects/commit.py:917`, `:931`) and on the tagger line in `git/objects/tag.py:129`. The published payload (letters plus an unterminated ` Tuple[int, int]: # Precompiled regexes -_re_actor_epoch = re.compile(r"^.+? (.*) (\d+) ([+-]\d+).*$") -_re_only_actor = re.compile(r"^.+? (.*)$") +# The leading field name ("author", "committer", "tagger") is matched with ``.[^ ]*`` rather than +# ``.+?``: both stop at the first space after the first c

Affected packages

Remediation: Upgrade to 3.2.0 or later.

References

• https://github.com/advisories/GHSA-m64x-33q8-m5h7