9.8

CVE-2023-23556: facebook hermes Out-of-bounds Write

CVSS: 9.8v3.1CriticalModified
Published 18-05-2023Last modified 31-01-2025
Open JSON

Vulnerability summary

CVE-2023-23556 is a critical (CVSS 9.8) Out-of-bounds Write vulnerability in facebook hermes. EPSS estimates a 0.89% chance of exploitation in the next 30 days, higher than 58.7% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.89%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 18-05-2023
    PublishedVulnerability first disclosed.
  2. 31-01-2025
    Last modifiedVulnerability information updated.

Description

An error in BigInt conversion to Number in Hermes prior to commit a6dcafe6ded8e61658b40f5699878cd19a481f80 could have been used by a malicious attacker to execute arbitrary code due to an out-of-bound write. Note that this bug is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.89%

Chance of exploitation in the next 30 days

Percentile

59%

Versus all other CVEs

30-day change

0.00 pp

From 0.89% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.89%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Facebook1 product
  • hermes< a6dcafe6ded8e61658b40f5699878cd19a481f80 | < 2023-02-02

1 vendor · 1 product

References

2 links