CVE-2026-109841 · GHSA-f72v-6w45-q472
undici vulnerable to Subresource Integrity bypass via non-lowercase algorithm tokens
- Risk score
- 58/100
- CVSS
- 7.5 v3.1
- Exploit chance (30 days)
- 0.3%
- Published
- 15 Oct 2026
Open in the live forecast Today's forecast
What to know
- What it 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 …
- Affected
- undici (npm) >= 7.15.0, < 7.30.1; undici (npm) >= 8.0.0, < 8.12.2
- Fix
- Upgrade undici to 7.30.1 or 8.12.2 (whichever matches your release line) or later.
- Exploitation
- No known exploitation
Story map
At a glance
Undici: Amber, patch this week. undici is an HTTP client library for Node.js. In versions 4.0.0 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, its Agent dispatcher passes its constructor options through a JSON-based deep clone before forwarding them to each per-origin pool, and because JSON cannot represent functions, a caller-suppl…
The flaws
- CVE-2026-109841: Undici vulnerable to Subresource Integrity bypass via non-lowercase algorithm tokens (CVSS 7.5 · EPSS 0%)
- CVE-2026-109383: Undici is an HTTP client library for Node.js (CVSS 9.1 · EPSS 0%)
- CVE-2026-109829: Undici is an HTTP client library for Node.js (CVSS 9.1 · EPSS 0%)
- CVE-2026-109932: Undici is an HTTP client library for Node.js (CVSS 7.5 · EPSS 0%)
The fix
Fix: Apply the vendor's security update; see the linked advisory.
Who is exposed: Undici
Where it stands
- No known exploitation
Connects to
- Same weakness: CWE-178 (CWE-178). 16 other warnings in 30 days
- Same product: Earlier undici warnings. 5 in the last 90 days
Why it is Yellow
- CVSS 7.5 high
- Remotely exploitable without logging in
- On your watchlist: npm
Affected packages
| Package | Ecosystem | Vulnerable | Fixed in |
|---|---|---|---|
| undici | npm | >= 7.15.0, < 7.30.1 | 7.30.1 |
| undici | npm | >= 8.0.0, < 8.12.2 | 8.12.2 |
References
- https://cna.openjsf.org/security-advisories.html
- https://github.com/nodejs/undici/security/advisories/GHSA-f72v-6w45-q472
- https://github.com/advisories/GHSA-f72v-6w45-q472
- https://nvd.nist.gov/vuln/detail/CVE-2026-109841
- https://github.com/nodejs/undici/commit/18bc8a1e09d15bc45815154a289dcf6fd5254d00
- https://github.com/nodejs/undici/commit/4f7ef6806e532ab9e29ccd6229b1b9d241e1b1f0
- https://github.com/nodejs/undici/releases/tag/v7.30.1
- https://github.com/nodejs/undici/releases/tag/v8.12.2
- https://github.com/advisories/GHSA-f72v-6w45-q472
Original description
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.
Last activity 23 Oct 2026. Patch Forecast updates every hour.