VulnerabilityDeferred

CVE-2026-12866

All versions of the package expr-eval are vulnerable to Code Execution via the toJSFunction() API.

CRITICAL 9.2EPSS 0.87%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.87%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

All versions of the package expr-eval are vulnerable to Code Execution via the toJSFunction() API. An attacker can execute arbitrary JavaScript by supplying crafted expressions that are compiled into native code using new Function(). Because user-controlled expressions are transformed directly into executable JavaScript, attackers can escape the intended expression sandbox and run arbitrary code within the application's context.

CVSS 4.0: 9.2 CRITICALCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.87% probability · 57th percentile
CISA KEV: Not listed
Weakness: CWE-94
Source: report@snyk.io

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.