Summary
snappy-java's Integer Overflow vulnerability in shuffle leads to DoS
Due to unchecked multiplications, an integer overflow may occur, causing a fatal error.
Description
The function shuffle(int[] input) in the file BitShuffle.java receives an array of integers and applies a bit shuffle on it. It does so by multiplying the length by 4 and passing it to the natively compiled shuffle function.
public static byte[] shuffle(int[] input) throws IOException {
byte[] output = new byte[input.length * 4];
int numProcessed = impl.shuffle(input, 0, 4, input.length * 4, output, 0);
assert(numProcessed == input.length * 4);
return output;
}
Since the length is not tested, the multiplication by four can cause an integer overflow and become a smaller value than the true size, or even zero or negative. In the case of a negative value, a “java.lang.NegativeArraySizeException” exception will raise, which can crash the program. In a case of a value that is zero or too small, the code that afterwards references the shuffled array will assume a bigger size of the array, which might cause exceptions such as “java.lang.ArrayIndexOutOfBoundsException”.
The same issue exists also when using the “shuffle” functions that receive a double, float, long and short, each using a different multiplier that may cause the same issue.
Steps To Reproduce
Compile and run the following code:
package org.example;
import org.xerial.snappy.BitShuffle;
import java.io.*;
public class Main {
public static void main(String[] args) throws IOException {
int[] original = new int[0x40000000];
byte[] shuffled = BitShuffle.shuffle(original);
System.out.println(shuffled[0]);
}
}
The program will crash, showing the following error (or similar):
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 0 out of bounds for length 0
at org.example.Main.main(Main.java:12)
Process finished with exit code 1
Alternatively - compile and run the following code:
package org.example;
import org.xerial.snappy.BitShuffle;
import java.io.*;
public class Main {
public static void main(String[] args) throws IOException {
int[] original = new int[0x20000000];
byte[] shuffled = BitShuffle.shuffle(original);
}
}
The program will crash with the following error (or similar):
Exception in thread "main" java.lang.NegativeArraySizeException: -2147483648
at org.xerial.snappy.BitShuffle.shuffle(BitShuffle.java:108)
at org.example.Main.main(Main.java:11)
Impact
Denial of Service
An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value. Typical impact: incorrect size calculations leading to heap overflows or logic errors.
CVE-2023-34453 has a CVSS score of 5.9 (Medium). 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 (1.1.10.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2023-34453? CVE-2023-34453 is a medium-severity integer overflow or wraparound vulnerability in org.xerial.snappy:snappy-java (maven), affecting versions <= 1.1.10.0. It is fixed in 1.1.10.1. An arithmetic operation produces a value that exceeds the integer type's maximum, causing it to wrap to an unexpected small value.
- How severe is CVE-2023-34453? CVE-2023-34453 has a CVSS score of 5.9 (Medium). 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.
- Which versions of org.xerial.snappy:snappy-java are affected by CVE-2023-34453? org.xerial.snappy:snappy-java (maven) versions <= 1.1.10.0 is affected.
- Is there a fix for CVE-2023-34453? Yes. CVE-2023-34453 is fixed in 1.1.10.1. Upgrade to this version or later.
- Is CVE-2023-34453 exploitable, and should I be worried? Whether CVE-2023-34453 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
- What actually determines whether CVE-2023-34453 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.
- How do I fix CVE-2023-34453? Upgrade
org.xerial.snappy:snappy-javato 1.1.10.1 or later.