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THREAT OPSThreat News › [GHSA] GHSA-ff84-5f28-78qj (medium) — re2: Out-of-bounds heap read in `exec`/`test`/`match` via attacker-influenced `lastIndex` on a non-ASCII subject → uncatchable process crash (DoS)

[GHSA] GHSA-ff84-5f28-78qj (medium) — re2: Out-of-bounds heap read in `exec`/`test`/`match` via attacker-influenced `lastIndex` on a non-ASCII subject → uncatchable process crash (DoS)

highgithub_advisoriesPublished 2026-07-31

GHSA-ff84-5f28-78qj Severity: medium CVE: 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)

## Summary

`re2` validates the user-settable `lastIndex` against the subject's **UTF-8 byte length** but then uses it as a **UTF-16 code-unit count** to walk the subject buffer, with no bounds

Indicators of compromise

Original source: https://github.com/advisories/GHSA-ff84-5f28-78qj