CVE-2025-12735: The expr-eval library is a JavaScript expression parser and evaluator designed to safely evaluate mathematical

This week

CRITICAL 9.8REMOTEDOWNGRADEUPGRADE

CVE-2025-12735 is a critical-severity flaw (CVSS 9.8) affecting javascript expression evaluator, javascript expression evaluator. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
CISA SSVC: public proof of concept
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.8% (top 22%)
CISA exploited list	No
Weakness	CWE-94
Published	2025-11-05
Last modified	2026-10-18

Publisher (CNA): CERT/CC · Vendor: jorenbroekema · silentmatt

Last updated 2026-10-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-11-05 01:15 UTCPublished CVE record published
2026-10-18 21:10 UTCUpdated Record last modified

jorenbroekema javascript expression evaluator DOWNGRADE

Affected: 3.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.0

1. Check installed version

npm ls javascript-expression-evaluator

2. No fixed release: DOWNGRADE to a release before 3.0.0

npm view javascript-expression-evaluator versions npm install javascript-expression-evaluator@"<3.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

silentmatt javascript expression evaluator UPGRADE

Affected: <= 2.0.2

Fixed in: newer than 2.0.2

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls javascript-expression-evaluator

2. UPGRADE to newer than 2.0.2

npm install javascript-expression-evaluator@">2.0.2"

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

npm · expr-eval · NO FIX YET · vulnerable: <= 2.0.2 · source

npm · expr-eval-fork · FIXED · 3.0.1 · vulnerable: <= 3.0.0 · source

npm install expr-eval-fork@">=3.0.1" npm ls expr-eval-fork

Fedora 46 · opensips · FIXED · 4.0.3-1.fc46 · FEDORA-2026-6700a0026c · source

sudo dnf upgrade --advisory=FEDORA-2026-6700a0026c

Fedora ELN · ibus-typing-booster · FIXED · 2.31.3-1.eln159 · FEDORA-2026-c895c68d60 · source

sudo dnf upgrade --advisory=FEDORA-2026-c895c68d60

RHEL 8 · grafana-pcp · NOT AFFECTED

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: alecasg555/safe-expr-eval (4 stars)
GitHub PoC: alnashawatirohwederb2167-max/cve-2025-12735-expr-eval-rce (0 stars)
GitHub PoC: AN5I/cve-2025-12735-expr-eval-rce (0 stars)
Write-up: github.com/jorenbroekema/expr-eval/blob/460b820ba01c5aca6c5d84a7d4f1fa5d1913c67b/test/secu

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-12735?

javascript expression evaluator: downgrade or apply the listed mitigation; javascript expression evaluator: upgrade to newer than 2.0.2. Exact commands for each OS are on this page.

Is CVE-2025-12735 being exploited?

CVE-2025-12735 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-12735 affect?

CVE-2025-12735 affects javascript expression evaluator, javascript expression evaluator. Severity is critical (CVSS 9.8). 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 ob

How urgent is CVE-2025-12735?

Priority 65/100. Critical severity; CISA SSVC: public proof of concept; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-13204 HIGH 7.3 MITIGATE npm package `expr-eval` is vulnerable to Prototype Pollution

References

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