CVE-2025-66219VulnerabilityPublished 29 Nov 2025Updated 1 Dec 2025

CVE-2025-66219: shama willitmerge · Command Injection

Affects shama willitmergeSource CVE Database V5

Not known to be exploited · CVSS 6.9 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

6.9Medium

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

EPSS: 2.6% chance of exploitation in 30 days – higher than 85% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/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: None
Vulnerable system integrity: Low
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: 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: 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 29 Nov 2025
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 2026-10-26.

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 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

Affected software

Product	Affected	Fixed in
npmwillitmerge`pkg:npm/willitmerge`Other threats	Affected <=0.2.1	Fixed in–

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

AI-suggested

Immediate mitigation involves discontinuing use of willitmerge versions 0.2.1 and earlier until a secure update is released. Organizations should audit their CI/CD pipelines to identify usage of willitmerge and isolate or sandbox its execution environment to limit potential damage from exploitation. Input validation and sanitization should be implemented at the integration points where user input reaches willitmerge, rejecting or escaping special shell characters. Consider replacing willitmerge with alternative tools that do not use unsafe command execution or that have verified secure coding practices. Monitoring and logging of CI/CD activities should be enhanced to detect anomalous command executions or unexpected merge behaviors. Engage with the vendor or open source maintainers to track patch releases and apply updates promptly. For critical environments, implement strict access controls around repository management and pull request approvals to reduce the risk of malicious input reaching willitmerge. Finally, educate developers and DevOps teams about the risks of command injection vulnerabilities and secure coding practices.

Description

willitmerge is a command line tool to check if pull requests are mergeable. In versions 0.2.1 and prior, there is a command Injection vulnerability in willitmerge. The vulnerability manifests in this package due to the use of insecure child process execution API (exec) to which it concatenates user input, whether provided to the command-line flag, or is in user control in the target repository. At time of publication, no known fix is public.

Impact

For European organizations, especially those with mature DevOps and CI/CD practices integrating willitmerge, this vulnerability poses a risk of unauthorized command execution within development environments. Attackers could manipulate pull request checks to inject malicious code or disrupt merge processes, potentially leading to compromised codebases or supply chain attacks. This could affect software integrity, delay development cycles, and introduce backdoors or vulnerabilities into production systems. The medium severity rating reflects limited impact on confidentiality and availability but a tangible threat to integrity. Organizations relying on automated merge checks in open source or internal repositories are particularly vulnerable. The absence of a patch increases exposure duration, and attackers exploiting this flaw could target critical infrastructure or sensitive projects, amplifying the impact. Additionally, compromised development tools could undermine trust in software supply chains, a key concern for European regulators and industries.

Summary

CVE-2025-66219 identifies a command injection vulnerability in the open-source command line tool willitmerge, developed by the shama project. willitmerge is designed to programmatically determine if pull requests can be merged, commonly integrated into CI/CD pipelines. Versions 0.2.1 and earlier use the Node.js exec API insecurely by concatenating user-controlled input directly into shell commands without neutralizing special characters or sanitizing inputs. This improper neutralization (CWE-77) allows an attacker to inject arbitrary shell commands that the system executes with the same privileges as the willitmerge process. The vulnerability can be triggered remotely without authentication or user interaction, as inputs can come from command-line flags or repository content under user control. Exploitation could allow attackers to execute arbitrary commands, potentially altering code, injecting malicious payloads, or disrupting development workflows. The CVSS 4.0 vector (AV:N/AC:L/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N) indicates network attack vector, low attack complexity, no privileges or user interaction required, and limited impact on integrity. No known exploits in the wild have been reported yet, but the vulnerability’s nature and ease of exploitation make it a significant risk for software supply chain security.

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection') (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #23OWASP Top 10 A05:2025: Injection (opens in a new tab)
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.
Architecture and Design
If at all possible, use library calls rather than external processes to recreate the desired functionality.
Implementation
If possible, ensure that all external commands called from the program are statically created.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
Attack patterns
LDAP Injection (opens in a new tab)
Command Delimiters (opens in a new tab)
IMAP/SMTP Command Injection (opens in a new tab)
Manipulating Writeable Terminal Devices (opens in a new tab)
Exploiting Multiple Input Interpretation Layers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Dec 2025, 04:29 UTC

WeaknessesCWE-77

Technical details

References

Community reviews

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