Algorithm Downgrade in Async-http-client - #VU142435
Published: August 13, 2026
Vulnerability identifier: #VU142435
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-757
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive credentials.
The vulnerability exists due to selection of a less-secure algorithm during negotiation in parseWWWAuthenticateHeader and parseProxyAuthenticateHeader when processing Digest authentication challenges without a usable nonce. A remote attacker can send a crafted WWW-Authenticate or Proxy-Authenticate challenge to disclose sensitive credentials.
This affects both origin and proxy authentication paths, and user interaction is not required.
Affected software
Async-http-client
Remediation
Install security update from vendor's website.
Async-http-client - addressed in versions 2.16.1, 3.0.13