CVE-2026-42077

CVE-2026-42077 is a medium-severity vulnerability with a CVSS 3.x base score of 5.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1321.

Key facts

Description

Evolver is a GEP-powered self-evolving engine for AI agents. Prior to version 1.69.3, a prototype pollution vulnerability in the mailbox store module allows attackers to modify the behavior of all JavaScript objects by injecting malicious properties into Object.prototype. The vulnerability exists in the _applyUpdate() and _updateRecord() functions which use Object.assign() to merge user-controlled data without filtering dangerous keys like __proto__, constructor, or prototype. This issue has been patched in version 1.69.3.

Frequently asked questions

What is CVE-2026-42077?
Evolver is a GEP-powered self-evolving engine for AI agents. Prior to version 1.69.3, a prototype pollution vulnerability in the mailbox store module allows attackers to modify the behavior of all JavaScript objects by injecting malicious properties into Object.prototype. The vulnerability exists in the _applyUpdate() and _updateRecord() functions which use Object.assign() to merge user-controlled data without filtering dangerous keys like __proto__, constructor, or prototype. This issue has been patched in version 1.69.3.
How severe is CVE-2026-42077?
CVE-2026-42077 has a CVSS 3.x base score of 5.2, rated medium severity. It is exploitable over local access with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability high.
Is CVE-2026-42077 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-42077?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42077 have an EU (EUVD) identifier?
Yes. CVE-2026-42077 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27012.
When was CVE-2026-42077 published?
CVE-2026-42077 was published on 2026-05-04 and last updated on 2026-06-17.

References

Other CWE-1321 (Prototype Pollution) vulnerabilities

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