Session Fixation in Async-http-client - #VU152424
Published: September 28, 2026
Vulnerability identifier: #VU152424
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-384
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to inject cookies into requests to other hosts.
The vulnerability exists due to incomplete origin checks in the default ThreadSafeCookieStore when processing Set-Cookie headers with Domain attributes from attacker-influenced origins. A remote attacker can cause a cookie to be stored under a key matched by a later request to a different host to inject cookies into requests to other hosts.
Exploitation requires a single AsyncHttpClient instance with its default cookie store enabled to access multiple origins, including an attacker-influenced origin.
Affected software
Async-http-client
Remediation
Install security update from vendor's website.
Async-http-client - update to 3.0.14