CVE-2023-4577

6.5 mediumEPSS 0.7%

Medium (6.5) in mozilla. EPSS 0.7% chance of exploitation in the next 30 days.

When `UpdateRegExpStatics` attempted to access `initialStringHeap` it could already have been garbage collected prior to entering the function, which could potentially have led to an exploitable crash. This vulnerability affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

Severity

CVSS 3.1

6.5 medium

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

EPSS: 0.7% chance of exploitation in the next 30 days; higher than 51% of CVEs (scores of 2026-10-31)
Published: 2023-09-11
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mozilla:firefox
mozilla:firefox_esr
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1847397
https://www.mozilla.org/security/advisories/mfsa2023-34/
https://www.mozilla.org/security/advisories/mfsa2023-36/
https://www.mozilla.org/security/advisories/mfsa2023-38/
https://bugzilla.mozilla.org/show_bug.cgi?id=1847397

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