🛡️ CVE-2026-16221 on Debian — node-ajv

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

Impact: fast-uri versions from 2.3.1 through 4.1.0 (including the 3.x line up to 3.1.3 and the 2.x line up to 2.4.2) do not treat a literal backslash character (U+005C) as an authority delimiter. Node's native WHATWG URL parser, used by fetch, undici, and Node's http and https clients, normalizes the backslash to a forward slash for special schemes such as http, https, ws, wss, ftp, and file. As a result, the two parsers extract different hosts from the same input string. Applications that use fast-uri to enforce host-based policy such as allowlists, denylists, loopback or SSRF filtering, redirect validation, or outbound proxy routing before passing the same URL into Node's URL or fetch consumers can be steered to an unintended destination, including cloud metadata endpoints, loopback, or internal hosts. Patches: upgrade to fast-uri 4.1.1, 3.1.4, or 2.4.3. Workarounds: none.

Distribution advisory

This page covers CVE-2026-16221 as tracked by Debian, for the package node-ajv. The fix is available in version 8.20.0~ds+~cs7.1.2-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity high, availability none.

Weakness class

DEBIAN-CVE-2026-16221 is classified as CWE-436: Interpretation Conflict. Two components parse the same data differently, so a check in one is bypassed in the other.

Affected software

DEBIAN-CVE-2026-16221 is recorded against 1 package.

node-ajv (fixed in 8.20.0~ds+~cs7.1.2-1)

Timeline and source

Published on 19 July 2026 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2026-07-19

Updated 2026-08-12

Modified 2026-08-06

Fix URL N/A

Affected Packages

Software	From version	Fixed in
node-ajv	—	8.20.0~ds+~cs7.1.2-1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2026-16221

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