CVE-2026-73621VulnerabilityPublished 14 Aug 2026Updated 26 Oct 2026

legit · GitPython: Arbitrary file truncation via git rev-list --output argument injection in unguarded Commit.count

Affects legitSource GCVE Database

Authoritative record:CVE-2026-73621· Medium 5.3

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.2.0.post0_13 when convenient.

Data as of 26 Oct 2026, 19:12 UTC

CVSS 4.0 base score

5.3Medium

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

Patch: Available – fixed in 1.2.0.post0_13

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/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: Low
Vulnerable system availability: Low
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to 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 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 legit to 1.2.0.post0_13.

Affected software

Product	Affected	Fixed in
Homebrewlegit`pkg:brew/legit`Other threats	Affected >=0.1.0 <1.2.0.post0_13	Fixed in 1.2.0.post0_13

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

AI-suggested

A patch is available in GitPython version 1.2.0.post0_13 that adds the necessary safety checks to Commit.count(). Users should upgrade to this version or later to remediate the vulnerability. Until patched, avoid passing untrusted input to Commit.count() keyword arguments, especially the output parameter.

Description

GitPython versions up to 3.1.53 contain a vulnerability in the Commit.count() method where unguarded forwarding of keyword arguments to git rev-list allows arbitrary file truncation. Specifically, using the output argument causes git rev-list to open and truncate the specified file to zero bytes before processing, enabling destruction of arbitrary files with the process's privileges. This vulnerability has a medium severity impact due to the integrity and availability loss but limited reachability and no content control over the truncation.

Impact

An attacker able to influence the output argument to Commit.count() can cause arbitrary files to be truncated to zero bytes with the privileges of the running process. This results in loss of file integrity and availability. The vulnerability does not allow content control or arbitrary file creation, and reachability is limited to contexts where the hexsha is controlled or predictable. Overall, the impact is medium severity.

Summary

The Commit.count() method in GitPython forwards **kwargs directly into the git rev-list command without the safety guard check_unsafe_options, unlike the sibling iter_items method. This allows an attacker to inject the --output argument to git rev-list, which opens and truncates the specified file to zero bytes before parsing revisions. As a result, calling commit.count(output='/victim') truncates the /victim file to zero bytes, causing arbitrary file destruction. This vulnerability affects GitPython versions up to 3.1.53 and was verified live. The issue is distinct from previously fixed vulnerabilities in iter_commits and blame methods, which had proper guards. The suggested fix is to add check_unsafe_options to Commit.count, mirroring the protection in iter_items.

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Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 19:12 UTC

Technical details

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