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Vulnerability · Published Aug 31, 2026 · Assigned by EEF

CVE-2026-75757AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a sibling subdomain

High 8.3

In plain English

A high-severity security flaw in ash_admin from ash-project. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).

Severity (CVSS 4.0)8.3High
Exploit odds (30 days)0.5%top 55.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Reliance on Cookies without Validation and Integrity Checking vulnerability in ash-project ash_admin lets an attacker who controls a sibling subdomain rebind an admin's session to a different actor, tenant, or authorization mode. AshAdmin's client JavaScript read its state cookies (tenant, actor_resource, actor_primary_key, actor_action, actor_domain, actor_authorizing, actor_paused) by matching the cookie name with an unanchored regular expression (new RegExp(name + "=([^;]+)")) against the whole document.cookie. Any cookie whose name merely ends with the requested name therefore matches, and whichever is serialized first wins. Because cookies are shared across a registrable domain, a compromised sibling subdomain can set a shadowing cookie (for example xactor_authorizing) with Domain=.example.com that flows unvalidated into the admin's LiveSocket connect params. The fix matches cookie names by exact equality. This issue affects ash_admin: from 0.9.1 before 1.3.1.

Affected products (as reported)

VendorProductVersions
ash-project ash_admin 0.9.1 – before 1.3.1
ash-project ash_admin 77a43cc4fa04cb59c38fc434568a35a38ecb995a – before e93a3408a85035e1f90275d02bc2470c96095e56

Weakness: CWE-565 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

References