nodejs undici up to 7.30.0/8.12.1 SRI Verification fetch input validation

Summaryinfo

A vulnerability identified as problematic has been detected in nodejs undici up to 7.30.0/8.12.1. Affected is the function fetch of the component SRI Verification. This manipulation causes input validation. This vulnerability appears as CVE-2026-109841. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in nodejs undici up to 7.30.0/8.12.1. It has been declared as problematic. Affected by this vulnerability is the function fetch of the component SRI Verification. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect integrity. The summary by CVE is:

undici is an HTTP client library for Node.js. In versions 7.15.0 through 7.30.0 and 8.0.0 through 8.12.1, its fetch() implementation verifies Subresource Integrity metadata by matching the algorithm token against a lowercase-only set, even though the SRI specification defines the token by its ASCII-lowercase form, so a valid but non-lowercase token such as an uppercase or mixed-case SHA256 is treated as unknown and skipped. When no recognized algorithm remains, undici treats the integrity list as empty and accepts the response, so a server returning a body that does not match the pinned digest passes the check. An attacker who controls only the response body can therefore deliver attacker-controlled bytes to an application that pinned a valid uppercase or mixed-case SRI token, with no integrity error, affecting response integrity only. The issue is fixed in undici 7.30.1 and 8.12.2, which normalize the algorithm token to ASCII lowercase before validation, and users should upgrade to one of those versions or later. As a workaround, use lowercase algorithm tokens such as sha256, sha384, or sha512 in integrity metadata.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-109841 since 10/13/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

Upgrading to version 7.30.1 or 8.12.2 eliminates this vulnerability.

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Productinfo

Vendor

• nodejs

Name

• undici

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17
• 7.18
• 7.19
• 7.20
• 7.21
• 7.22
• 7.23
• 7.24
• 7.25
• 7.26
• 7.27
• 7.28
• 7.29
• 7.30.0
• 8.12.0
• 8.12.1

Website

• Product: https://github.com/nodejs/undici/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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