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TI-2023-09387 Aliases CVE-2023-23556GHSA-5wwx-r37w-hqhw

Out-of-bounds write in Meta Hermes

Priority MEDIUM 51CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00891 59th percentileScored 2026-11-07
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

No affected products listed by the sources yet.

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:facebook:hermes:*:*:*:*:*:*:*:*before 2023-02-02VulnerableMeta
  • cpe:2.3:a:facebook:hermes:*:*:*:*:*:*:*:* Versions before 2023-02-02 Vulnerable ·Meta

Remediation

No fixed version listed by the sources yet.

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Facebook Hermes a6dcafe6ded8e61658b40f5699878cd19a481f80

    2 records Highest priority Priority MEDIUM 2 MEDIUM

    Other records, highest priority first

    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-23556
  2. 2026-10-03 Alias added: GHSA-5wwx-r37w-hqhw

References

Patch 2

  • TI-2023-14306 Use after free in Meta Hermes CVSS 3.1CRITICAL 9.8
  • TI-2023-12661 Use after free in Meta Hermes CVSS 3.1CRITICAL 9.8
  • TI-2023-11181 Type confusion in Meta Hermes CVSS 3.1CRITICAL 9.8
  • TI-2023-09388 Type confusion in Meta Hermes CVSS 3.1CRITICAL 9.8
  • TI-2020-01841 A logic vulnerability when handling the SaveGeneratorLong instruction in Facebook Hermes… CVSS 3.1CRITICAL 9.8
  • TI-2020-01823 Stack-based buffer overflow in Meta Hermes CVSS 3.1CRITICAL 9.8
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences