Is CVE-2026-1526 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-1526 being exploited in the wild.

How severe is CVE-2026-1526?

High severity, with a CVSS score of 7.5, published 12 March 2026.

Which products and versions are affected?

undici (npm) SEMVER:introduced=0,fixed=6.24.0.

Is there a fix for CVE-2026-1526?

Yes. undici (npm): upgrade to 6.24.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-1526 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-1526?

Check whether you run undici (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-1526: Node.js undici DoS via unbounded WebSocket decompression memory consumption

CVE-2026-1526 · Severity: high · CVSS 7.5 · Published 2026-03-12

The undici WebSocket client, a popular tool for handling web connections in Node.js applications, is vulnerable to a denial-of-service attack. A malicious server can send a specially crafted, highly compressed message (known as a "decompression bomb") that forces the client to consume massive amounts of memory. This can cause the application to crash or become completely unresponsive, potentially disrupting business operations and service availability.

Technologies: undici (npm). Vendors: npm.

Quick answers

Is CVE-2026-1526 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-1526 being exploited in the wild.
How severe is CVE-2026-1526?: High severity, with a CVSS score of 7.5, published 12 March 2026.
Which products and versions are affected?: undici (npm) SEMVER:introduced=0,fixed=6.24.0.
Is there a fix for CVE-2026-1526?: Yes. undici (npm): upgrade to 6.24.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-1526 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-1526?: Check whether you run undici (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

undici (npm): upgrade to 6.24.0 or later
```
npm install undici@6.24.0
```

Technical details

The vulnerability is classified as a resource exhaustion issue (CWE-409/CWE-770) within the undici WebSocket client's handling of the 'permessage-deflate' extension. Specifically, the PerMessageDeflate.decompress() method fails to enforce limits on the size of decompressed data, accumulating chunks in memory before concatenation. A remote attacker controlling a WebSocket server can exploit this by sending a small compressed frame that expands significantly upon decompression. This results in unbounded memory consumption, leading to a process crash (OOM) or system unresponsiveness. The attack requires no authentication and is reachable over the network if the client connects to a malicious endpoint.

Affected products

Node.js undici

Identifiers

CVE-2026-1526
GHSA-vrm6-8vpv-qv8q

Timeline

2026-03-12: advisory: Advisory published by OpenJS Foundation and NVD

References

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