CVE-2026-42076: Evolver: Command Injection via `execSync` in `_extractLLM()` function allows Remote Code Execution

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 2.6%, percentile 85: FIRST’s model estimates a 2.6% chance of exploitation activity in the next 30 days, higher than 85% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes @evomap/evolver (npm) < 1.69.3, fixed in 1.69.3. Check your lockfile, including transitive dependencies.

What it is

Evolver is a GEP-powered self-evolving engine for AI agents. Prior to version 1.69.3, a command injection vulnerability in the extractLLM() function allows attackers to execute arbitrary shell commands on the server. The function constructs a curl command using string concatenation and passes it to execSync() without proper sanitization, enabling remote code execution when the corpus parameter contains shell metacharacters. This issue has been patched in version 1.69.3.

From the GitHub advisory

Summary A command injection vulnerability in the extractLLM() function allows attackers to execute arbitrary shell commands on the server. The function constructs a curl command using string concatenation and passes it to execSync() without proper sanitization, enabling remote code execution when the corpus parameter contains shell metacharacters.

Details The vulnerability exists in src/gep/signals.js at lines 260-274:

The corpus parameter is derived from user input (via userSnippet in extractSignals() function) and flows through to extractLLM() where it becomes part of the shell command. While JSON.stringify() escapes some characters, it does not prevent shell command substitution via $(...) syntax when the resulting string is passed to execSync().

The extractSignals() function is called from the main evolution loop in src/gep/evolver.js, which processes user snippets and session transcripts.

PoC

Weakness type: CWE-78.

Product: @evomap/evolver (npm) · Assigned by: GitHub_M · Published: 2026-05-04

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 2.56% probability of exploitation activity in the next 30 days; percentile 85.

Timeline

• 2026-04-22 — GitHub-reviewed advisory GHSA-j5w5-568x-rq53 published (critical)
• 2026-05-04 — CVE record published by GitHub_M
• 2026-05-05 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-j5w5-568x-rq53 github.com
2. CVE.org record CVE-2026-42076 cve.org
3. NVD entry CVE-2026-42076 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

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