Summary When parsing unknown fields in the Protobuf Java Lite and Full library, a maliciously crafted message can cause a StackOverflow error and lead to a program crash.

Reporter: Alexis Challande, Trail of Bits Ecosystem Security Team <ecosystem@trailofbits.com>

Affected versions: This issue affects all versions of both the Java full and lite Protobuf runtimes, as well as Protobuf for Kotlin and JRuby, which themselves use the Java Protobuf runtime.

Severity CVE-2024-7254 High CVSS4.0 Score 8.7 (NOTE: there may be a delay in publication) This is a potential Denial of Service. Parsing nested groups as unknown fields with DiscardUnknownFieldsParser or Java Protobuf Lite parser, or against Protobuf map fields, creates unbounded recursions that can be abused by an attacker.

Proof of Concept For reproduction details, please refer to the unit tests (Protobuf Java LiteTest and CodedInputStreamTest) that identify the specific inputs that exercise this parsing weakness.

Remediation and Mitigation We have been working diligently to address this issue and have released a mitigation that is available now. Please update to the latest available versions of the following packages: protobuf-java (3.25.5, 4.27.5, 4.28.2) protobuf-javalite (3.25.5, 4.27.5, 4.28.2) protobuf-kotlin (3.25.5, 4.27.5, 4.28.2) protobuf-kotlin-lite (3.25.5, 4.27.5, 4.28.2) com-protobuf [JRuby gem only] (3.25.5, 4.27.5, 4.28.2)

A parsing issue with binary data in protobuf-java core and lite versions prior to 3.21.7, 3.20.3, 3.19.6 and 3.16.3 can lead to a denial of service attack. Inputs containing multiple instances of non-repeated embedded messages with repeated or unknown fields causes objects to be converted back-n-forth between mutable and immutable forms, resulting in potentially long garbage collection pauses. We recommend updating to the versions mentioned above.