GHSA-2M67-WJPJ-XHG9

Jackson Core 3.x does not consistently enforce StreamReadConstraints.maxDocumentLength. Oversized JSON documents can be accepted without a StreamConstraintsException in multiple parser entry points, which allows configured size limits to be bypassed and weakens denial-of-service protections.

Details

Three code paths where maxDocumentLength is not fully enforced:

1. Blocking parsers skip validation of the final in-memory buffer

Blocking parsers validate only previously processed buffers, not the final in-memory buffer:

• ReaderBasedJsonParser.java:255
• UTF8StreamJsonParser.java:208

Relevant code:

_currInputProcessed += bufSize;
_streamReadConstraints.validateDocumentLength(_currInputProcessed);

This means the check occurs only when a completed buffer is rolled over. If an oversized document is fully contained in the final buffer, parsing can complete without any document-length exception.

2. Async parsers skip validation of the final chunk on end-of-input

Async parsers validate previously processed chunks, but do not validate the final chunk on end-of-input:

• NonBlockingByteArrayJsonParser.java:49
• NonBlockingByteBufferJsonParser.java:57
• NonBlockingUtf8JsonParserBase.java:75

Relevant code:

_currInputProcessed += _origBufferLen;
_streamReadConstraints.validateDocumentLength(_currInputProcessed);

public void endOfInput() {
    _endOfInput = true;
}

endOfInput() marks EOF but does not perform a final validateDocumentLength(...) call, so an oversized last chunk is accepted.

3. DataInput parser path does not enforce maxDocumentLength at all

• JsonFactory.java:457

Relevant construction path:

int firstByte = ByteSourceJsonBootstrapper.skipUTF8BOM(input);
return new UTF8DataInputJsonParser(readCtxt, ioCtxt,
        readCtxt.getStreamReadFeatures(_streamReadFeatures),
        readCtxt.getFormatReadFeatures(_formatReadFeatures),
        input, can, firstByte);

UTF8DataInputJsonParser does not call StreamReadConstraints.validateDocumentLength(...), so maxDocumentLength is effectively disabled for createParser(..., DataInput) users.

Note: This issue appears distinct from the recently published nesting-depth and number-length constraint advisories because it affects document-length enforcement.

PoC

Async path reproducer

import java.nio.charset.StandardCharsets;
import tools.jackson.core.JsonParser;
import tools.jackson.core.ObjectReadContext;
import tools.jackson.core.StreamReadConstraints;
import tools.jackson.core.async.ByteArrayFeeder;
import tools.jackson.core.json.JsonFactory;

public class Poc {
    public static void main(String[] args) throws Exception {
        JsonFactory factory = JsonFactory.builder()
                .streamReadConstraints(StreamReadConstraints.builder()
                        .maxDocumentLength(10L)
                        .build())
                .build();

        byte[] doc = "{\"a\":1,\"b\":2}".getBytes(StandardCharsets.UTF_8);

        try (JsonParser p = factory.createNonBlockingByteArrayParser(ObjectReadContext.empty())) {
            ByteArrayFeeder feeder = (ByteArrayFeeder) p.nonBlockingInputFeeder();
            feeder.feedInput(doc, 0, doc.length);
            feeder.endOfInput();

            while (p.nextToken() != null) { }
        }

        System.out.println("Parsed successfully");
    }
}

• Expected result: Parsing should fail because the configured document-length limit is 10, while the input is longer than 10 bytes.
• Actual result: The document is accepted and parsing completes.

Blocking path reproducer

import java.io.ByteArrayInputStream;
import java.nio.charset.StandardCharsets;
import tools.jackson.core.JsonParser;
import tools.jackson.core.StreamReadConstraints;
import tools.jackson.core.json.JsonFactory;

public class Poc2 {
    public static void main(String[] args) throws Exception {
        JsonFactory factory = JsonFactory.builder()
                .streamReadConstraints(StreamReadConstraints.builder()
                        .maxDocumentLength(10L)
                        .build())
                .build();

        byte[] doc = "{\"a\":1,\"b\":2}".getBytes(StandardCharsets.UTF_8);

        try (JsonParser p = factory.createParser(new ByteArrayInputStream(doc))) {
            while (p.nextToken() != null) { }
        }

        System.out.println("Parsed successfully");
    }
}

Applications that rely on maxDocumentLength as a safety control for untrusted JSON can accept oversized inputs without error. In network-facing services this weakens an explicit denial-of-service protection and can increase CPU and memory consumption by allowing larger-than-configured request bodies to be processed.

The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.

GHSA-2M67-WJPJ-XHG9 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.1.1); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is GHSA-2M67-WJPJ-XHG9? GHSA-2M67-WJPJ-XHG9 is a high-severity allocation of resources without limits or throttling vulnerability in tools.jackson.core:jackson-core (maven), affecting versions >= 3.0.0, <= 3.1.0. It is fixed in 3.1.1. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
2. How severe is GHSA-2M67-WJPJ-XHG9? GHSA-2M67-WJPJ-XHG9 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of tools.jackson.core:jackson-core are affected by GHSA-2M67-WJPJ-XHG9? tools.jackson.core:jackson-core (maven) versions >= 3.0.0, <= 3.1.0 is affected.
4. Is there a fix for GHSA-2M67-WJPJ-XHG9? Yes. GHSA-2M67-WJPJ-XHG9 is fixed in 3.1.1. Upgrade to this version or later.
5. Is GHSA-2M67-WJPJ-XHG9 exploitable, and should I be worried? Whether GHSA-2M67-WJPJ-XHG9 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-2M67-WJPJ-XHG9 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-2M67-WJPJ-XHG9? Upgrade tools.jackson.core:jackson-core to 3.1.1 or later.