SEPTEMBER 19, 2026
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Case File

CVE-2026-16729

MEDIUM · CVSS 4.8 EPSS 0.19% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-07-29 · Last synced 2026-08-28

CyberRota Analysis

AI-Generated

The vulnerability lies in the setCookie function of undici, which fails to properly sanitize cookie attributes, allowing attackers to manipulate cookie settings through user-controlled input. This can lead to bypassing SameSite CSRF protections and altering security attributes like Secure and HttpOnly, particularly affecting applications that manage session cookies based on tenant-supplied domains. Developers and security teams using affected versions of undici should prioritize upgrading to the patched versions to mitigate these risks.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

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CVE
CVE-2026-16729
Severity
MEDIUM
CVSS
4.8
EPSS
0.19%

Original NVD 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.

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