Skip to content
CVE PROGRAM SOURCE RECORD4.8 Medium

CVE-2026-16729

undici vulnerable to cookie attribute injection via unsanitized domain and unparsed setCookie fields

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

undici undici

Default version status: unaffected

  • 0 to < 6.28.0affected
  • 6.28.0unaffected
  • 7.0.0 to < 7.29.0affected
  • 7.29.0unaffected
  • 8.0.0 to < 8.9.0affected
  • 8.9.0unaffected
pkg:npm/undici

References