The MessageDigest.isEqual function in Java Runtime Environment (JRE) in Sun Java SE in JDK and JRE 5.0 before Update 22, JDK and JRE 6 before Update 17, SDK and JRE 1.3.x before 1.3.1_27, and SDK and JRE 1.4.x before 1.4.2_24 allows remote attackers to spoof HMAC-based digital signatures, and possibly bypass authentication, via unspecified vectors related to "timing attack vulnerabilities," aka Bug Id 6863503.
Weaknesses in this category are related to the design and implementation of data confidentiality and integrity. Frequently these deal with the use of encoding techniques, encryption libraries, and hashing algorithms. The weaknesses in this category could lead to a degradation of the quality data if they are not addressed.