CVE-2026-71498: uhop node-re2 out-of-bounds heap read in replace and split

CVE-2026-71498 · Severity: medium · CVSS 5.1 · Published 2026-08-06

A vulnerability in the node-re2 library, which provides high-performance regular expression support for Node.js, could allow an attacker to read small amounts of sensitive information from the computer's memory. By providing specially crafted data (specifically a Buffer ending in a partial character), an attacker can trick the software into reading past the end of the intended data and returning adjacent memory contents. This could lead to the exposure of fragments of other data processed by the application, potentially impacting privacy and security.

Technologies: re2 (npm), Uhop Re2. Vendors: npm, Uhop.

Quick answers

Is CVE-2026-71498 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-71498 being exploited in the wild.
How severe is CVE-2026-71498?
Medium severity, with a CVSS score of 5.1, published 6 August 2026.
Which products and versions are affected?
re2 (npm) SEMVER:introduced=0,fixed=1.26.1; Uhop Re2 <= 1.26.0.
Is there a fix for CVE-2026-71498?
Yes. re2 (npm): upgrade to 1.26.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-71498 attacked?
It is attacked with local access, in a software library.
Am I affected by CVE-2026-71498?
Check whether you run re2 (npm) or Uhop Re2 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • re2 (npm): upgrade to 1.26.1 or later
    npm install re2@1.26.1

Technical details

The node-re2 library suffers from an out-of-bounds (OOB) heap read vulnerability in its native C++ layer. The `getUtf8CharSize` function determines character length based solely on the lead byte without verifying the actual remaining buffer length. When a `Buffer` object (which is passed to the native layer without re-encoding) ends with a multi-byte UTF-8 lead byte but lacks the necessary continuation bytes, functions like `replace()` and `split()` will read up to 3 bytes past the buffer boundary. These adjacent heap bytes are then copied into the resulting JavaScript object, allowing for deterministic information disclosure. The vulnerability is fixed in version 1.26.1 by clamping the inferred character size to the actual remaining input length.

Affected products

  • uhop re2 <= 1.26.0

Identifiers

  • CVE-2026-71498
  • GHSA-j4r3-hg7j-8chg

Timeline

  • 2026-07-21: disclosed: Reported by OvOhao
  • 2026-08-06: advisory: GitHub Advisory published
  • 2026-08-06: patched: Fixed in version 1.26.1

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.