CVE-2023-23556

9.8 criticalEPSS 0.9%

Critical (9.8) in facebook hermes. EPSS 0.9% chance of exploitation in the next 30 days.

An error in BigInt conversion to Number in Hermes prior to commit a6dcafe6ded8e61658b40f5699878cd19a481f80 could have been used by a malicious attacker to execute arbitrary code due to an out-of-bound write. Note that this bug is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.

Severity

CVSS 3.1

9.8 critical

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

EPSS: 0.9% chance of exploitation in the next 30 days; higher than 59% of CVEs (scores of 2026-10-31)
CWE: CWE-787
Published: 2023-05-18
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

facebook:hermes

References

https://github.com/facebook/hermes/commit/a6dcafe6ded8e61658b40f5699878cd19a481f80
https://www.facebook.com/security/advisories/cve-2023-23556
https://github.com/facebook/hermes/commit/a6dcafe6ded8e61658b40f5699878cd19a481f80
https://www.facebook.com/security/advisories/cve-2023-23556

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