How severe is CVE-2023-24807?

CVE-2023-24807 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-24807?

CVE-2023-24807 affects the following packages: undici (npm). Ecosystems affected: npm.

How do I fix CVE-2023-24807?

Update undici to 5.19.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-24807 is resolved across your whole dependency graph.

How do I detect CVE-2023-24807 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for undici, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-24807 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2023-24807 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-24807 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-24807?

CVE-2023-24807 has an EPSS (Exploit Prediction Scoring System) score of 1.3%, placing it in the 71th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-24807?

CVE-2023-24807 is classified as Improper Input Validation (CWE-20), CWE-1333 (CWE-1333). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-24807 published, and has it been updated?

CVE-2023-24807 was published on February 16, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

HIGH severity

CVE-2023-24807 — undici

HIGHFix: nodejs/undici@f2324e5

CVE-2023-24807 is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in undici. A fix is available for undici — see the affected versions and patch details below.

Undici vulnerable to Regular Expression Denial of Service in Headers

Also known asGHSA-r6ch-mqf9-qc9w

Published

Feb 16, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-24807.

EPSS Exploitation Probability

via FIRST.org ↗

1.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs71th percentile — riskier than 71% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

9Kother npm packages depend on this — each one inherits the vulnerability until it's patched upstream

undicinpm

312.7Mdownloads / week

Description

Impact

The Headers.set() and Headers.append() methods are vulnerable to Regular Expression Denial of Service (ReDoS) attacks when untrusted values are passed into the functions. This is due to the inefficient regular expression used to normalize the values in the headerValueNormalize() utility function.

Patches

This vulnerability was patched in v5.19.1.

Workarounds

There is no workaround. Please update to an unaffected version.

References

https://hackerone.com/bugs?report_id=1784449

Credits

Carter Snook reported this vulnerability.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`undici`	all versions	5.19.1`npm install undici@5.19.1`

Affected Products

1 product · 1 configurations

Application

undicinodejs

< 5.19.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for undici, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update undici to 5.19.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-24807 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

Product	Fixed in	Advisory
Red Hat Enterprise Linux 8	`nodejs:16-8070020230314140722.bd1311ed`	RHSA-2023:1582
Red Hat Enterprise Linux 8	`nodejs:18-8070020230322080930.bd1311ed`	RHSA-2023:1583
Red Hat Enterprise Linux 9	`nodejs:18-9020020230327152102.rhel9`	RHSA-2023:2654
Red Hat Enterprise Linux 9	`nodejs-1:16.19.1-1.el9_2`	RHSA-2023:2655
Red Hat Enterprise Linux 9.0 Extended Update Support	`nodejs-1:16.20.2-1.el9_0`	RHSA-2023:5533

Frequently Asked Questions

### Impact The `Headers.set()` and `Headers.append()` methods are vulnerable to Regular Expression Denial of Service (ReDoS) attacks when untrusted values are passed into the functions. This is due to the inefficient regular expression used to normalize the values in the `headerValueNormalize()` utility function. ### Patches This vulnerability was patched in v5.19.1. ### Workarounds There is no workaround. Please update to an unaffected version. ### References * https://hackerone.com/bugs?report_id=1784449 ### Credits Carter Snook reported this vulnerability.