by Kastro
Paper/Archive/CVE-2026-12866

CVE-2026-12866

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

EPSS 0.9%public exploitCVSS 9.8
critical.is priorityof 100
51
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 58.7.587 × 2011.7Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
expr-evalall versions–CNA
org.webjars.npm:expr-evalall versions–CNA

Scores by source

snyk (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
snyk (CNA)9.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: poc · Automatable: yes · Technical impact: total

References

exploitsecurity.snyk.io/vuln/SNYK-JS-EXPREVAL-15054690refsecurity.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-17662018refgithub.com/silentmatt/expr-eval/blob/master/src/expression.js%23L55refgithub.com/silentmatt/expr-eval/issues/292