CVE-2026-73620VulnerabilityPublished 14 Aug 2026Updated 26 Oct 2026

IndexFile.checkout() · GitPython: Unguarded git option forwarding

Affects cf2tfSource GCVE Database

Authoritative record:CVE-2026-73620· High 7.2

Not known to be exploited · CVSS 7.2 High : upgrade to 0.9.2_7 soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score

7.2High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.9.2_7

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: High
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: High: There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade cf2tf to 0.9.2_7.

Affected software

Product	Affected	Fixed in
Homebrewcf2tf`pkg:brew/cf2tf`Other threats	Affected >=0.6.1 <0.9.2_7	Fixed in 0.9.2_7

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

**Target:** gitpython-developers/GitPython **Tested:** HEAD `07e80555` (2026-07-25), latest release 3.1.55, `git version 2.50.1` **Reported instances:** 2 exploitable, from a sweep of 14 unguarded call sites ## Summary GitPython blocks dangerous git options through `Git.check_unsafe_options()`, gated per method by an `allow_unsafe_options` parameter. That guard is applied **per call site**, so any API that forwards `**kwargs` into a git command without calling it passes caller-controlled options straight to git. A mechanical sweep of every method that forwards `**kwargs` into a `.git.<command>(...)` call found **14 sites with no guard**. Two reach a git option that takes a filesystem path: | # | Call site | git option | Impact | |---|---|---|---| | 1 | `IndexFile.checkout()` → `git checkout-index` | `--prefix=<path>` | arbitrary file **overwrite** with repository-controlled content | | 2 | `TagReference.create()` → `git tag` | `-F <file>` / `--file=<file>` | arbitrary file **read**, returned in-band | This is the same defect class already fixed in `Commit.count()` (GHSA-p538-c434-8v24), `Repo.archive()` and `Git.ls_remote()` (GHSA-956x-8gvw-wg5v). Both instances below are still present at HEAD. --- ## Instance 1 — `IndexFile.checkout()`: arbitrary file overwrite `git/index/base.py:1210` accepts `**kwargs` and forwards them with no guard: ```python def checkout(self, paths=None, force=False, fprogress=lambda *args: None, **kwargs): ... proc = self.repo.git.checkout_index(*args, **kwargs) # line 1331 ... proc = self.repo.git.checkout_index(args, **kwargs) # line 1349 ``` There is no `allow_unsafe_options` parameter and no `check_unsafe_options()` call in the method. `git checkout-index` accepts `--prefix=<string>`, prepended to every output path. It is not confined to the working tree, so an absolute prefix writes tracked file contents anywhere the process can write, and `-f` overwrites what is already there. ### Reproduction ```python from git import Repo Repo("/path/to/repo").index.checkout(prefix="/tmp/target_dir/", a=True, f=True) ``` Observed (`poc/poc_checkout_index.py`) — no exception raised, files land outside the repository: ``` [ALLOWED] no UnsafeOptionError raised files written outside the repo: ['f.txt'] f.txt: 'hi\n' ``` Overwrite of a pre-existing file (`poc/poc_ci_overwrite.py`) — the victim file held `ORIGINAL-DO-NOT-CLOBBER\n` before the call: ``` [ALLOWED] no exception victim content now: 'hi\n' OVERWRITTEN: True ``` ### Why this rates High Both halves of the write are attacker-influenced: - **Destination** — the `prefix` kwarg. - **Content** — the bytes written are repository blobs, so anyone who can land a file in the repository (a pull-request branch, a mirrored or untrusted repository, an agent-cloned repository) controls exactly what is written. Commit a file named `authorized_keys`, `.bashrc`, `config` or `post-checkout`, choose the matching prefix (`~/.ssh/`, `~/`, `.git/hooks/`), and the write becomes code execution as the service account. For comparison within this project: GHSA-fjr4-x663-mwxc (arbitrary file overwrite via `git diff --output`) is rated High, and GHSA-p538-c434-8v24 (arbitrary file *truncation* via `git rev-list --output`) is rated Medium. `--prefix` supplies full content control, so it sits at or above the former. --- ## Instance 2 — `TagReference.create()`: arbitrary file read `git/refs/tag.py:88` forwards `**kwargs` into `git tag` with no guard, and the signature advertises the passthrough: ```python def create(cls, repo, path, reference="HEAD", logmsg=None, force=False, **kwargs): """... :param kwargs: Additional keyword arguments to be passed to :manpage:`git-tag(1)`. """ ``` `git tag` accepts `-F <file>` / `--file=<file>`, which reads the tag message from an arbitrary path. The annotated tag object stores that content and GitPython returns it to the caller via `TagReference.tag.message`, so the file contents come back in-band. ### Reproduction ```python from git import Repo from git.refs.tag import TagReference t = TagReference.create(Repo("/path/to/repo"), "x", force=True, a=True, F="/etc/passwd") print(t.tag.message) ``` Observed (`poc/poc_tag_F.py`), reading a canary file outside the repository: ``` [ALLOWED] no UnsafeOptionError raised >>> tag message recovered from arbitrary path: 'TAG-READ-CANARY-98765\nsecond-line-secret' ``` Impact is a read at the privileges of the process. I am not claiming code execution for this instance. The signing options (`-s`, `-u`/`--local-user`) do invoke gpg from the same unguarded kwargs, but I did not develop that into command execution and make no claim about it. --- ## Sweep results — the other 12 sites Reported so the fix can be scoped once rather than per report. `poc/sweep.py` reproduces this list. | Call site | git command | Assessment | |---|---|---| | `IndexFile.from_tree()` | `read-tree` | `--index-output=<path>` looked reachable but i

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