CVE-2026-78677VulnerabilityPublished 4 Sep 2026Updated 26 Oct 2026

cf2tf · GitPython: clone_from()/clone() omit --separate-git-dir from unsafe_git_clone_options, enabling arbitrary

Affects cf2tfSource GCVE Database

Authoritative record:CVE-2026-78677· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 0.9.2_9 soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score

8.7High

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.9.2_9

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

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: None
Vulnerable system availability: None
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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
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 25 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_9.

Affected software

Product	Affected	Fixed in
Homebrewcf2tf`pkg:brew/cf2tf`Other threats	Affected >=0.6.1 <0.9.2_9	Fixed in 0.9.2_9

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

Description

- **CWE:** CWE-73 (External Control of File Name or Path) / CWE-22 (Path Traversal, in the "escapes intended base directory" sense) - **Affected component:** `git/repo/base.py`, `Repo.unsafe_git_clone_options` (class attribute, lines 153-165) and `Repo._clone()` (lines 1477-1520), reached via the public `Repo.clone_from()` (line 1626) and `Repo.clone()` (line 1567) APIs. - **Affected version:** GitPython at HEAD (`9729ed3b948f2bde09f1f188c5311e172212b67e`, 2026-08-05, VERSION `3.1.58`) ## Reachability `Repo.clone_from(url, to_path, **kwargs)` (and `Repo.clone()`) forward arbitrary keyword arguments to the underlying `git clone` invocation. Before forwarding, GitPython builds a candidate option list from the kwargs (`Git._option_candidates`) and checks it against a denylist, `Repo.unsafe_git_clone_options`, via `Git.check_unsafe_options()` — *unless* the caller passes `allow_unsafe_options=True`. This denylist mechanism is exactly the guard that the last ~16 published GHSAs against this repo (2026-07-12 → 2026-08-05) have repeatedly found incomplete or bypassable for other options (`--template`, `--upload-pack`, `--config`, `--exec`, `--output`, `--index-output`, `--pathspec-from-file`, etc.). `git clone` also accepts `--separate-git-dir=<path>`, which redirects the repository's entire `.git` metadata directory to an **arbitrary, caller-controlled filesystem path**, leaving only a gitlink text file (`gitdir: <path>`) at the intended destination. This is the exact same primitive already recognized as unsafe by GitPython's own code: `Repo.unsafe_git_init_options` (line 145-150) blocks `--separate-git-dir` for `Repo.init()`, with the comment *"Redirects the repository metadata to a caller-controlled path"*. The `Repo._clone()`/`clone()`/`clone_from()` docstring (line 1450-1452) is even more explicit: ``` :param allow_unsafe_options: Allow unsafe options to be used, such as ``--template`` and ``--separate-git-dir``. ``` i.e. the maintainers' own documentation states that `allow_unsafe_options=False` (the default) is supposed to block `--separate-git-dir` for clone. But **`Repo.unsafe_git_clone_options` does not contain it**: ```python unsafe_git_clone_options = [ "--upload-pack", "-u", "--config", "-c", "--template", "--bundle-uri", ] ``` So any application that forwards a `separate_git_dir` (or `separate-git-dir`) kwarg into `Repo.clone_from()` / `Repo.clone()` — e.g. a CI/build service, a Git-hosting proxy, or any tool that exposes a subset of clone options to a client, the exact threat model already accepted for the sibling `--template`/`--upload-pack`/`--config` entries in this same list — gets **no protection at all** for `--separate-git-dir`, even with the default `allow_unsafe_options=False`. ## Root cause Parity gap between two sibling denylists that guard the same underlying primitive (arbitrary redirection of git metadata storage): `unsafe_git_init_options` correctly lists `--separate-git-dir`; `unsafe_git_clone_options`, covering the same option on a different git subcommand that also accepts it, does not — despite the function's own docstring claiming otherwise. This is the same "denylist omits an equally-dangerous sibling option" pattern already responsible for `GHSA-539m-9xh6-q6rr` (`archive` denylist missing `--add-file`/`--add-virtual-file`) and `GHSA-6p8h-3wgx-97gf` (`clone` denylist missing `--template`, since fixed). ## Exploit path 1. Attacker-controlled input reaches a `separate_git_dir=...` (or equivalently `"separate-git-dir"`) keyword argument passed into `Repo.clone_from()` / `Repo.clone()` by the host application, with `allow_unsafe_options` left at its default `False`. 2. `Git._option_candidates()` renders this as `--separate-git-dir` and `Git.check_unsafe_options()` checks it against `Repo.unsafe_git_clone_options` — no match, no `UnsafeOptionError` raised. 3. `Git.transform_kwargs()` renders the same kwarg into the real command line as `--separate-git-dir=<attacker path>` and GitPython executes `git clone -v --separate-git-dir=<attacker path> -- <url> <dest>` via `subprocess` (no shell). 4. `git` itself creates the full repository metadata tree (`config`, `description`, `HEAD`, `hooks/`, `index`, `objects/`, `refs/`, `packed-refs`, `logs/`) at the attacker-specified path — which can be **any path outside the intended clone destination** that the process has permission to create — and leaves a gitlink file at the intended destination pointing to it. ## Impact Arbitrary directory/file creation at a path fully controlled by the attacker (bounded only by filesystem permissions of the process running GitPython), matching the impact class of the already-published, High-severity `GHSA-hmq2-w58f-27jc` ("Arbitrary Git Repository Creation Outside the Working Tree", CVSS 8.2). Concretely: - Planting a git repository structure (including a `hooks/` directory) at an attacker-chosen location outside the sandboxed clone destination the calling application in

References

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