Summary
Evolver has Prototype Pollution via Object.assign() in its mailbox store operations
Impact
This is a Prototype Pollution vulnerability that can lead to:
- Property injection affecting all JavaScript objects
- Authentication/authorization bypass
- Application logic manipulation
- Denial of service via prototype corruption
- Potential remote code execution if polluted properties affect security-critical code paths
Attack requirements: The attacker needs write access to the messages.jsonl file. This could be achieved through:
- File upload vulnerabilities
- Path traversal (combined with the Arbitrary File Write vulnerability in the fetch command)
- Compromised backup files
- Shared hosting environments
Affected users: Anyone using the mailbox functionality in multi-user environments or with persistent message storage.
CVE-2026-42077 has a CVSS score of 5.2 (Medium). The vector is requires local access, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.69.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-42077? CVE-2026-42077 is a medium-severity security vulnerability in @evomap/evolver (npm), affecting versions < 1.69.3. It is fixed in 1.69.3.
- How severe is CVE-2026-42077? CVE-2026-42077 has a CVSS score of 5.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of @evomap/evolver are affected by CVE-2026-42077? @evomap/evolver (npm) versions < 1.69.3 is affected.
- Is there a fix for CVE-2026-42077? Yes. CVE-2026-42077 is fixed in 1.69.3. Upgrade to this version or later.
- Is CVE-2026-42077 exploitable, and should I be worried? Whether CVE-2026-42077 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-42077 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-42077? Upgrade
@evomap/evolverto 1.69.3 or later.