CVE-2021-24037 json
Use After Free in Hermes
published 2021-06-15 5 y ago modified 2026-06-17 4 mo ago also GHSA-mph8-6787-r8hw , EUVD-2022-4601
- cvss
- 9.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.8%
- EPSS 1.8% chance of exploitation in 30 days, percentile 78%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
Exploit prediction
1.80% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 7.5 | AV:N/AC:L/Au:N/C:P/I:P/A:P |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | hermes-engine | <0.8.0 |
0.8.0 |
Affected products
- Facebook Hermes
Classification
- Weakness
-
- CWE-416 Use After Free
References
-
github.com
/facebook/hermes/commit/d86e185e485b6330216dee8e854455c694e3a36e
web, patch, third-party-advisory
-
facebook.com
/security/advisories/CVE-2021-24037
web, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-24037
advisory
-
github.com
/facebook/hermes
package
Sources
- CVE List CVE-2021-24037
- GitHub Advisory GHSA-mph8-6787-r8hw
- NVD CVE-2021-24037
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.