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GitProxy New Branch Approval Exploit

High severity GitHub Reviewed Published Jul 30, 2025 in finos/git-proxy • Updated Jul 31, 2025

Package

npm @finos/git-proxy (npm)

Affected versions

<= 1.19.1

Patched versions

1.19.2

Description

Summary

An attacker can exploit the way GitProxy handles new branch creation to bypass the approval of prior commits on the parent branch.

Because it can greatly affect system integrity, we classify this as a High impact vulnerability.

Details

GitProxy checks for the 0000000000000000000000000000000000000000 hash to detect new branches. This is used to process the commit accordingly in both getDiff.ts and parsePush.ts. However, the logic can be exploited as follows:

  1. Make a commit in branch a (could be main)
  2. Make a new branch b from that commit
  3. Make a new commit in b, then approve it/get it approved
  4. Go back to a, and attempt to push this commit to the proxy

The unapproved commit from a will be pushed to the remote.

PoC

To reproduce this vulnerability:

  1. Clone the target repository and make an unapproved commit on a mainline branch (e.g. main):
git checkout -b a origin/main
echo "DEBUG=true" > config.env
git add config.env
git commit -m "Sensitive debug config"
git push proxy a
  1. Without approving/getting the commit approved on branch a, create a new branch b based on it:
git checkout -b b
echo "feature x implemented" > feature.txt
git add feature.txt
git commit -m "Feature implementation"
git push proxy b

  1. Approve/get approval for the push to branch b.

  2. Now attempt to push the original unapproved commit from branch a:

git checkout a
git push proxy a

Prior to 1.19.2, this results in unapproved commits from a getting pushed without any policy checks or explicit approval.

From 1.19.2 onwards, this flow will allow pushing all commits to branch b (and explicit approval will be asked for the changes on b only). However, commits on branch a now require approval on push. If merging branch b into a, this also requires explicit approval of the (previously unapproved) commits originating from a to prevent loopholes.

Impact

The vulnerability impacts all users or organizations relying on GitProxy to enforce policy and prevent unapproved changes. It requires no elevated privileges beyond regular push access, and no extra user interaction. It does however, require a GitProxy administrator or designated user (canUserApproveRejectPush) to approve pushes to the child branch.

References

@coopernetes coopernetes published to finos/git-proxy Jul 30, 2025
Published to the GitHub Advisory Database Jul 30, 2025
Reviewed Jul 30, 2025
Published by the National Vulnerability Database Jul 30, 2025
Last updated Jul 31, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required Low
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality None
Integrity High
Availability None
Subsequent System Impact Metrics
Confidentiality None
Integrity High
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N

EPSS score

Weaknesses

Improper Authorization

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Learn more on MITRE.

CVE ID

CVE-2025-54585

GHSA ID

GHSA-39p2-8hq9-fwj6

Source code

Credits

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