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TI-2020-01839 Aliases CVE-2020-1912GHSA-pf27-929j-9pmm

Out-of-bounds write in Meta Hermes

Priority LOW 39CWE-787Published · Updated

Key facts

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

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

Summary

An out-of-bounds read/write vulnerability when executing lazily compiled inner generator functions in Facebook Hermes prior to commit 091835377369c8fd5917d9b87acffa721ad2a168 allows attackers to potentially execute arbitrary code via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.

Why it matters now

EPSS 0.01813 78th percentileScored 2026-11-07
Fix Fixed hermes-engine (npm): 0.5.2

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MetaHermescommit prior to 091835377369c8fd5917d9b87acffa721ad2a168—No fix listedCNA
—hermes-engine (npm)before 0.5.20.5.2Patch availableGHSA-pf27-929j-9pmm
  • Hermes VendorMeta Affected commit prior to 091835377369c8fd5917d9b87acffa721ad2a168 Fixed in — No fix listed CNA
  • hermes-engine (npm) Vendor— Affected before 0.5.2 Fixed in 0.5.2 Patch available GHSA-pf27-929j-9pmm

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:facebook:hermes:*:*:*:*:*:*:*:*up to 0.4.3VulnerableMeta
  • cpe:2.3:a:facebook:hermes:*:*:*:*:*:*:*:* Versions up to 0.4.3 Vulnerable ·Meta

Remediation

  • Fix · GHSA-pf27-929j-9pmm hermes-engine (npm) Fixed in 0.5.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-1912
  2. 2026-10-03 Alias added: GHSA-pf27-929j-9pmm

References

Patch 1

Advisory 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-2023-09387 Out-of-bounds write 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
See all 19 →

Sources

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