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Fencer Intel
high 8.1

CVE-2020-1912 json

Out-of-bounds Read and Out-of-bounds Write in Facebook Hermes

published 6y ago modified 4mo ago also GHSA-pf27-929j-9pmm , EUVD-2022-4748

cvss
8.1
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

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.

Patch / fix

  • npm hermes-engine 0.5.2

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Exploit prediction

1.81% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
npm hermes-engine
<0.5.2
0.5.2

Affected products

  • Facebook Hermes

Classification

Weakness

References

Sources

Fencer Intel 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.