CVE-2025-12735: silentmatt expr-eval · Code Injection
Affects silentmatt expr-evalSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 1.7% chance of exploitation in 30 days – higher than 77% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 5 Nov 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
npmexpr-evalpkg:npm/expr-evalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Immediate mitigation steps include monitoring for updates or patches from the silentmatt project and applying them as soon as they become available. Until a patch is released, organizations should implement strict input validation and sanitization on all data passed to the expr-eval library, especially the context object and its members. Avoid evaluating expressions that incorporate untrusted or user-supplied data. Employ runtime application self-protection (RASP) or web application firewalls (WAF) to detect and block suspicious expression evaluation patterns. Conduct thorough code reviews to identify and refactor usage of expr-eval in critical systems. Consider isolating or sandboxing components that perform expression evaluation to limit potential damage from exploitation. Additionally, enhance logging and alerting around expression evaluation failures or anomalies to enable rapid detection of exploitation attempts. Educate developers about the risks of dynamic code evaluation and promote safer alternatives where feasible.
Description
The expr-eval library is a JavaScript expression parser and evaluator designed to safely evaluate mathematical expressions with user-defined variables. However, due to insufficient input validation, an attacker can pass a crafted context object or use MEMBER of the context object into the evaluate() function and trigger arbitrary code execution.
References
- github.com/silentmatt/expr-eval (opens in a new tab)
- github.com/jorenbroekema/expr-eval (opens in a new tab)
- npmjs.com/package/expr-eval-fork (opens in a new tab)
- npmjs.com/package/expr-eval (opens in a new tab)
- github.com/silentmatt/expr-eval/pull/288 (opens in a new tab)
- github.com/advisories/GHSA-jc85-fpwf-qm7x (opens in a new tab)
- kb.cert.org/vuls/id/263614 (opens in a new tab)
- github.com/jorenbroekema/expr-eval/blob/460b820ba01c5aca6c5d84a7d4f1fa5d1913c67b/test/security.js (opens in a new tab)
- kb.cert.org/vuls/id/263614 (opens in a new tab)