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

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

Affects nbdimeSource GCVE Database

Authoritative record:CVE-2026-78677· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 4.0.4_8 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 4.0.4_8

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 nbdime to 4.0.4_8.

Affected software

Product	Affected	Fixed in
Homebrewnbdime`pkg:brew/nbdime`Other threats	Affected >=1.1.0 <4.0.4_8	Fixed in 4.0.4_8

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

AI-suggested

A fix is available in GitPython version 4.0.4_8. Users and maintainers should upgrade to this version or later to ensure --separate-git-dir is properly blocked by default. Until upgraded, avoid passing the separate_git_dir or separate-git-dir keyword arguments to Repo.clone_from() or Repo.clone(), or explicitly set allow_unsafe_options=True only if fully trusted and aware of the risks. Review any applications or services that expose clone options to clients to ensure they do not forward this unsafe option.

Description

GitPython versions >=1.1.0 and <4.0.4_8 contain a vulnerability where the clone_from() and clone() methods do not block the --separate-git-dir option by default, despite documentation stating otherwise. This allows an attacker controlling input to specify an arbitrary filesystem path for the Git metadata directory during cloning, potentially creating files and directories outside the intended clone destination. The vulnerability arises from an incomplete denylist of unsafe git clone options, omitting --separate-git-dir, which is recognized as unsafe in other contexts within GitPython.

Impact

An attacker able to control input to Repo.clone_from() or Repo.clone() can cause arbitrary creation of Git repository metadata directories and files at attacker-chosen filesystem paths outside the intended clone destination. This can include planting hooks or other files in locations that may affect system behavior or security, limited only by the permissions of the process running GitPython. The vulnerability has a CVSS score of 7.5 (High) with network attack vector, low complexity, no privileges required, and no user interaction needed. There is no known exploitation in the wild at this time.

Summary

GitPython's Repo.clone_from() and Repo.clone() methods forward keyword arguments to the underlying git clone command, filtering unsafe options via a denylist (Repo.unsafe_git_clone_options). However, the --separate-git-dir option, which redirects the repository's .git metadata directory to an arbitrary path, is missing from this denylist. Although the documentation states that allow_unsafe_options=False (default) should block --separate-git-dir, the omission allows attacker-controlled input to specify this option, causing git clone to create repository metadata at an attacker-controlled location on the filesystem. This can lead to arbitrary directory and file creation outside the intended clone destination, bounded only by the filesystem permissions of the process running GitPython. The root cause is a parity gap between denylist entries for git init and git clone commands. The vulnerability is fixed in GitPython version 4.0.4_8.

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What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 17:15 UTC

Technical details

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