What is CVE-2025-47279?

CVE-2025-47279 is a low-severity security vulnerability in undici (npm), affecting versions < 5.29.0. It is fixed in 5.29.0, 6.21.2, 7.5.0.

How severe is CVE-2025-47279?

CVE-2025-47279 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of undici are affected by CVE-2025-47279?

undici (npm) versions < 5.29.0 is affected.

Is there a fix for CVE-2025-47279?

Yes. CVE-2025-47279 is fixed in 5.29.0, 6.21.2, 7.5.0. Upgrade to this version or later.

Is CVE-2025-47279 exploitable, and should I be worried?

Whether CVE-2025-47279 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2025-47279 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2025-47279?

Upgrade: undici to 5.29.0 or later, undici to 6.21.2 or later, undici to 7.5.0 or later.

CVE-2025-47279 in undici

Q: How severe is CVE-2025-47279?

CVE-2025-47279 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of undici are affected by CVE-2025-47279?

undici (npm) versions < 5.29.0 is affected.

Q: Is there a fix for CVE-2025-47279?

Yes. CVE-2025-47279 is fixed in 5.29.0, 6.21.2, 7.5.0. Upgrade to this version or later.

Q: Is CVE-2025-47279 exploitable, and should I be worried?

Whether CVE-2025-47279 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2025-47279 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2025-47279?

Upgrade: undici to 5.29.0 or later, undici to 6.21.2 or later, undici to 7.5.0 or later.

Summary

undici Denial of Service attack via bad certificate data

Workarounds

If a webhook fails, avoid keep calling it repeatedly.

References

Reported as: https://github.com/nodejs/undici/issues/3895

Impact

Applications that use undici to implement a webhook-like system are vulnerable. If the attacker set up a server with an invalid certificate, and they can force the application to call the webhook repeatedly, then they can cause a memory leak.

CVE-2025-47279 has a CVSS score of 3.1 (Low). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (5.29.0, 6.21.2, 7.5.0); upgrading removes the vulnerable code path.

Affected versions

undici (< 5.29.0) undici (>= 6.0.0, < 6.21.2) undici (>= 7.0.0, < 7.5.0)

Security releases

undici → 5.29.0 (npm) undici → 6.21.2 (npm) undici → 7.5.0 (npm)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

This has been patched in https://github.com/nodejs/undici/pull/4088.

Frequently Asked Questions

What is CVE-2025-47279? CVE-2025-47279 is a low-severity security vulnerability in undici (npm), affecting versions < 5.29.0. It is fixed in 5.29.0, 6.21.2, 7.5.0.
How severe is CVE-2025-47279? CVE-2025-47279 has a CVSS score of 3.1 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of undici are affected by CVE-2025-47279? undici (npm) versions < 5.29.0 is affected.
Is there a fix for CVE-2025-47279? Yes. CVE-2025-47279 is fixed in 5.29.0, 6.21.2, 7.5.0. Upgrade to this version or later.
Is CVE-2025-47279 exploitable, and should I be worried? Whether CVE-2025-47279 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2025-47279 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2025-47279?
- Upgrade undici to 5.29.0 or later
- Upgrade undici to 6.21.2 or later
- Upgrade undici to 7.5.0 or later

Other vulnerabilities in undici

CVE-IDSeverityPackage summary

CVE-2026-11525Lowundici: undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching CVE-2026-12151Highundici: undici WebSocket client vulnerable to denial of service via fragment count bypass CVE-2026-9679Mediumundici: undici vulnerable to HTTP header injection via Set-Cookie percent-decoding CVE-2026-6734Highundici: undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse CVE-2026-6733Lowundici: undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse