CVE-2021-24037
A use after free in hermes, while emitting certain error messages, prior to commit d86e185e485b6330216dee8e854455c694e3a36e allows attackers to potentially execute arbitrary code via crafted JavaScript.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.80%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A use after free in hermes, while emitting certain error messages, prior to commit d86e185e485b6330216dee8e854455c694e3a36e 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.
- 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
- 1.80% probability · 78th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- facebook/hermes
- Source
- cve-assign@fb.com
EPSS 1.8% 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/d86e185e485b6330216dee8e854455c694e3a36ePatch, Third Party Advisory
- https://www.facebook.com/security/advisories/CVE-2021-24037Vendor Advisory
- https://github.com/facebook/hermes/commit/d86e185e485b6330216dee8e854455c694e3a36ePatch, Third Party Advisory
- https://www.facebook.com/security/advisories/CVE-2021-24037Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.