CVE-2021-24045
A type confusion vulnerability could be triggered when resolving the "typeof" unary operator in Facebook Hermes prior to v0.10.0.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.25%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A type confusion vulnerability could be triggered when resolving the "typeof" unary operator in Facebook Hermes prior to v0.10.0. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.25% probability · 69th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-843
- Affected
- facebook/hermes
- Source
- cve-assign@fb.com
EPSS 1.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/facebook/hermes/commit/55e1b2343f4deb1a1b5726cfe1e23b2068217ff2Patch, Third Party Advisory
- https://www.facebook.com/security/advisories/cve-2021-24045Vendor Advisory
- https://github.com/facebook/hermes/commit/55e1b2343f4deb1a1b5726cfe1e23b2068217ff2Patch, Third Party Advisory
- https://www.facebook.com/security/advisories/cve-2021-24045Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.