Information Exposure Through Timing Discrepancy in dnsjava - #VU162703
Published: November 9, 2026
Vulnerability identifier: #VU162703
CSH Severity: Low
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-208
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker who knows a TSIG key name to obtain timing information about matching portions of a message authentication code.
The vulnerability exists due to a non-constant-time MAC comparison in dnsjava's TSIG verification that stops at the first difference. An unauthenticated remote attacker can resend a fixed message with varying MAC bytes to observe timing differences, although current JDK behavior makes remote exploitation appear impractical.
Affected software
dnsjava
Remediation
Install security update from vendor's website.
dnsjava - update to 3.7.0