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Medium severity4.8NVD Advisory· Published Jul 29, 2026· Updated Aug 5, 2026

CVE-2026-16729

CVE-2026-16729

Description

undici's setCookie function does not fully sanitize cookie attributes. In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, a domain value is not checked for semicolons and entries in the unparsed array are not sanitized, so attacker-influenced input can inject additional cookie attributes. For example, a domain value containing a semicolon can append attributes such as SameSite, and an unparsed entry can inject attributes such as HttpOnly, without the caller setting them. Applications that pass user-controlled input to these fields, such as multi-tenant or reverse-proxy servers that scope session cookies to a tenant-supplied domain, can have SameSite CSRF protections bypassed, or the Secure, HttpOnly, and SameSite attributes forced, stripped, or overridden. The issue is fixed in undici 6.28.0, 7.29.0, and 8.9.0.

AI Insight

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Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
undicinpm
< 6.28.06.28.0
undicinpm
>= 7.0.0, < 7.29.07.29.0
undicinpm
>= 8.0.0, < 8.9.08.9.0

Affected products

33

Patches

Vulnerability mechanics

References

10

News mentions

1