CVE-2023-30470: A use-after-free related to unsound inference in the bytecode generation when optimizations are enabled for He

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CRITICAL 9.8REMOTEMITIGATE

CVE-2023-30470 is a critical-severity flaw (CVSS 9.8) affecting hermes. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A use-after-free related to unsound inference in the bytecode generation when optimizations are enabled for Hermes prior to commit da8990f737ebb9d9810633502f65ed462b819c09 could have been used by an attacker to achieve remote code execution. Note that this is only exploitable in cases where Hermes is used to execute untrusted JavaScript. Hence, most React Native applications are not affected.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-416
Published	2023-05-18
Last modified	2026-06-17

Publisher (CNA): Facebook, Inc. · Vendor: facebook

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-05-18 22:15 UTCPublished CVE record published
2026-06-17 05:54 UTCUpdated Record last modified

facebook hermes MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy hermes || rpm -q hermes || hermes --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-30470?

hermes: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-30470 being exploited?

CVE-2023-30470 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-30470 affect?

CVE-2023-30470 affects hermes. Severity is critical (CVSS 9.8). A use-after-free related to unsound inference in the bytecode generation when optimizations are enabled for Hermes prior to commit da8990f737ebb9d9810633502f65ed462b819c09 could have been used by an attacker to achieve remote code execution

How urgent is CVE-2023-30470?

Priority 57/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

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References

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