diff --git a/meta/recipes-devtools/python/python3-git/CVE-2026-73621.patch b/meta/recipes-devtools/python/python3-git/CVE-2026-73621.patch
new file mode 100644
index 0000000000..bb1050645e
--- /dev/null
+++ b/meta/recipes-devtools/python/python3-git/CVE-2026-73621.patch
@@ -0,0 +1,72 @@
+From 3186ded297a9818f887c3de47fc2f0aba6a8b298 Mon Sep 17 00:00:00 2001
+From: Sebastian Thiel <sebastian.thiel@icloud.com>
+Date: Sat, 25 Jul 2026 06:27:01 +0200
+Subject: [PATCH] fix: reject unsafe output options in Commit.count
+
+<!-- agent -->
+
+Commit.count forwards keyword arguments to git rev-list but did not apply the
+unsafe-option validation used by the sibling revision APIs.
+
+Validate forwarded options with the existing Git.check_unsafe_options helper
+and retain the explicit allow_unsafe_options escape hatch. This covers
+GHSA-p538-c434-8v24 without adding another option parser.
+
+Git baseline: git.git a23bace963 defines --output as a shared diff option
+consumed by setup_revisions; t/t6000-rev-list-misc.sh exercises that option
+with rev-list.
+
+CVE: CVE-2026-73621
+Upstream-Status: Backport [https://github.com/gitpython-developers/GitPython/commit/38553b6fddc7f6a667cdb45a6762343a08fc72b2]
+
+Backport Changes:
+- Omitted test/test_commit.py because the current PyPI source 
+  archive does not include the test suite and the python3-git 
+  recipe does not run it.
+
+Co-authored-by: GPT 5.6 <codex@openai.com>
+(cherry picked from commit 38553b6fddc7f6a667cdb45a6762343a08fc72b2)
+Signed-off-by: Yogita Urade <yurade@cisco.com>
+---
+ git/objects/commit.py | 15 ++++++++++++++-
+ 1 file changed, 14 insertions(+), 1 deletion(-)
+
+diff --git a/git/objects/commit.py b/git/objects/commit.py
+index cc85e7dd..549e12c7 100644
+--- a/git/objects/commit.py
++++ b/git/objects/commit.py
+@@ -269,13 +269,21 @@ class Commit(base.Object, TraversableIterableObj, Diffable, Serializable):
+         else:
+             return self.message.split(b"\n", 1)[0]
+ 
+-    def count(self, paths: Union[PathLike, Sequence[PathLike]] = "", **kwargs: Any) -> int:
++    def count(
++        self,
++        paths: Union[PathLike, Sequence[PathLike]] = "",
++        allow_unsafe_options: bool = False,
++        **kwargs: Any,
++    ) -> int:
+         """Count the number of commits reachable from this commit.
+ 
+         :param paths:
+             An optional path or a list of paths restricting the return value to commits
+             actually containing the paths.
+ 
++        :param allow_unsafe_options:
++            Allow unsafe options, like ``--output``.
++
+         :param kwargs:
+             Additional options to be passed to :manpage:`git-rev-list(1)`. They must not
+             alter the output style of the command, or parsing will yield incorrect
+@@ -284,6 +292,11 @@ class Commit(base.Object, TraversableIterableObj, Diffable, Serializable):
+         :return:
+             An int defining the number of reachable commits
+         """
++        if not allow_unsafe_options:
++            Git.check_unsafe_options(
++                options=Git._option_candidates([], kwargs), unsafe_options=self.unsafe_git_rev_options
++            )
++
+         # Yes, it makes a difference whether empty paths are given or not in our case as
+         # the empty paths version will ignore merge commits for some reason.
+         if paths:
diff --git a/meta/recipes-devtools/python/python3-git_3.1.43.bb b/meta/recipes-devtools/python/python3-git_3.1.43.bb
index 6456031620..f712a0e699 100644
--- a/meta/recipes-devtools/python/python3-git_3.1.43.bb
+++ b/meta/recipes-devtools/python/python3-git_3.1.43.bb
@@ -32,6 +32,7 @@ SRC_URI += "file://CVE-2026-42284.patch \
            file://CVE-2026-73623.patch \
            file://CVE-2026-73624.patch \
            file://CVE-2026-73622.patch \
+           file://CVE-2026-73621.patch \
            "
 SRC_URI[sha256sum] = "35f314a9f878467f5453cc1fee295c3e18e52f1b99f10f6cf5b1682e968a9e7c"