CVE-2025-62491: A Use-After-Free (UAF) vulnerability exists in the QuickJS engine's standard library when iterating over the g

Q: How do I fix CVE-2025-62491?

quickjs: upgrade to 2025-09-13. Exact commands for each OS are on this page.

Q: Is CVE-2025-62491 being exploited?

CVE-2025-62491 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-62491 affect?

CVE-2025-62491 affects quickjs. Severity is high (CVSS 8.8). A Use-After-Free (UAF) vulnerability exists in the QuickJS engine's standard library when iterating over the global list of unhandled rejected promises (ts->rejected_promise_list). * The function js_std_promise_rejection_check attempts

This month

HIGH 8.8UPGRADE

CVE-2025-62491 is a high-severity flaw (CVSS 8.8) affecting quickjs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A Use-After-Free (UAF) vulnerability exists in the QuickJS engine's standard library when iterating over the global list of unhandled rejected promises (ts->rejected_promise_list). * The function js_std_promise_rejection_check attempts to iterate over the rejected_promise_list to report unhandled rejections using a standard list loop. * The reason for a promise rejection is processed inside the loop, including calling js_std_dump_error1(

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 65%)
CISA exploited list	No
Weakness	CWE-416
Published	2025-10-16
Last modified	2026-10-19

Publisher (CNA): Google Inc. · Vendor: quickjs project

Last updated 2026-10-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-10-16 16:15 UTCPublished CVE record published
2026-10-19 16:10 UTCUpdated Record last modified

quickjs project quickjs UPGRADE

Affected: < 2025-09-13

Fixed in: 2025-09-13

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 2025-09-13 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade quickjs

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade quickjs

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2025-62491?

quickjs: upgrade to 2025-09-13. Exact commands for each OS are on this page.

Is CVE-2025-62491 being exploited?

CVE-2025-62491 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-2025-62491 affect?

CVE-2025-62491 affects quickjs. Severity is high (CVSS 8.8). A Use-After-Free (UAF) vulnerability exists in the QuickJS engine's standard library when iterating over the global list of unhandled rejected promises (ts->rejected_promise_list). * The function js_std_promise_rejection_check attempts

How urgent is CVE-2025-62491?

Priority 45/100. High severity; Public exploit reference

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References

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