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Arbitrary Command Injection due to Improper Command Sanitization in Git URLs specified as Custom Behaviors

Critical
emma-sg published GHSA-47vv-v544-r985 Jun 8, 2026

Package

docker webrecorder/browsertrix-backend (Docker)

Affected versions

>=1.15.0 <1.22.8

Patched versions

>=1.22.8

Description

Impact

Any user with "crawler" or "admin" access to a Browsertrix instance version >=1.15.0 <1.22.8 can run arbitrary commands on the pod running the Browsertrix's back-end, which includes access to the instance's database, configured storage bucket(s), and any configured proxy servers.

An attacker may be able to access, modify, and delete the following:

  • Email addresses, hashed passwords, and associated organizations of users
  • Archived items and their metadata, including both crawls and uploads
  • Saved browser profiles, including cookies and other stored browser data which may include credentials to any website that a user logged into for the purpose of crawling
  • Back-ups of archived items, browser profiles, and other stored data
  • SSH keys for any configured proxy servers

Additionally, where configured (such as on Webrecorder's hosted Browsertrix instance), they may be able to access:

  • Associated external subscription information of organizations
  • User-facing billing information such as past purchases & subscription history, billing addresses, truncated credit card information (last 4 digits)

For self-hosted users of Browsertrix, the ability to exploit this vulnerability is limited to users with "crawler" or "admin" permission on the specific instance of Browsertrix. If you have enabled open registration, you are at risk, please upgrade or patch immediately. If you have not, the ability to exploit will be limited to existing crawler users on your instance, so the risk is somewhat lower; please still upgrade as soon as possible though.

For Webrecorder's hosted instance, the potential impact was wider, as anyone was able to sign up for a free trial and be granted access as an admin to their own org.

At the moment we have not found any indication that this vulnerability was known or exploited in the wild. We are continuing to investigate.

Patches

The vulnerability has been patched in Browsertrix 1.22.8 and later. We recommend rotating secrets (such as database credentials, storage bucket keys, and SSH keys for proxy servers) after updating.

Upgrading will depend on how you deploy Browsertrix, in most cases you should be able to re-run the command used to deploy previously with the new version. We have instructions for updating a cluster with Helm in our docs.

Please reach out to us if you need a hand.

Workarounds

If you are not able to update your Browsertrix instance, this vulnerability can be worked around by preventing API calls with paths matching /api/orgs/*/crawlconfigs/validate/custom-behavior (where * matches any string) from reaching the api container. This could be implemented with a custom firewall between pods, or by modifying the api container's nginx config file.

Severity

Critical

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 None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality High
Integrity High
Availability High

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:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVE ID

CVE-2026-54501

Weaknesses

Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Learn more on MITRE.

Improper Neutralization of Special Elements used in a Command ('Command Injection')

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component. Learn more on MITRE.

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Learn more on MITRE.

Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')

The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string. Learn more on MITRE.

Execution with Unnecessary Privileges

The product performs an operation at a privilege level that is higher than the minimum level required, which creates new weaknesses or amplifies the consequences of other weaknesses. Learn more on MITRE.

Credits