CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
62.1%
The BCP 47 tag parser has quadratic time complexity due to inherent aspects of its design. Since the parser is, by design, exposed to untrusted user input, this can be leveraged to force a program to consume significant time parsing Accept-Language headers. The parser cannot be easily rewritten to fix this behavior for various reasons. Instead the solution implemented in this CL is to limit the total complexity of tags passed into ParseAcceptLanguage by limiting the number of dashes in the string to 1000. This should be more than enough for the majority of real world use cases, where the number of tags being sent is likely to be in the single digits.
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
AI Score
Confidence
High
EPSS
Percentile
62.1%