re2: Global String.prototype.match with an empty-matchable pattern never advances → infinite loop with unbounded native memory growth (DoS)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.2 · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-68499: 0.18% estimated exploitation activity in the next 30 days; percentile 8.01 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary String.prototype.match with a global RE2 collects all matches in a native loop that advances the cursor by the match length. A zero-width (empty) match has length 0, so the cursor never advances: the same empty match is found forever and appended to an ever-growing native vector. Any pattern that can match the empty string (a, b?, x{0,3}, (a)|, (?:), …) therefore causes an infinite loop with unbounded memory growth. The call is synchronous native code, so it blocks the entire event loop and cannot be interrupted by try/catch, AbortController, --max-old-space-size, or timers — the process must be killed externally. This diverges from the built-in engine, where 'xxxx'.match(/a/g) returns a finite array. Root cause When match.size() == 0, byteIndex is unchanged, so the next iteration matches the same empty position again; groups grows without bound. The other iteration paths already guard this: lib/split.cc:50-55 advances by getUtf8CharSize on an empty match, and exec advances…

Published by the source

31 Jul 2026, 16:53 UTC

Last modified by the source

31 Jul 2026, 16:53 UTC

Source last checked

26 Oct 2026, 13:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6hxr-mr5r-9836

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# Patch Next advisory brief: CVE-2026-68499

Advisory: re2: Global `String.prototype.match` with an empty-matchable pattern never advances → infinite loop with unbounded native memory growth (DoS)
IDs: CVE-2026-68499, GHSA-6hxr-mr5r-9836
Record: https://patchnext.com/advisories/cve-2026-68499 (revision 1, source checked 26 Oct 2026, 13:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: re2 1.25.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm re2: affected <= 1.25.1; fixed in 1.25.2

## Suggested inspection (read-only)
- `npm ls re2 --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on re2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6hxr-mr5r-9836 (GitHub-reviewed advisory GHSA-6hxr-mr5r-9836 lists affected ranges: npm re2 >=0 <=1.25.1)

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