Summary
Buffer Overflow in yajl-ruby
NOTE: A previous patch, 1.4.2, fixed the heap memory issue, but could still lead to a DoS infinite loop. Please update to version 1.4.3
The 1.x branch and the 2.x branch of yajl contain an integer overflow which leads to subsequent heap memory corruption when dealing with large (~2GB) inputs.
Details
The reallocation logic at yajl_buf.c#L64 may result in the need 32bit integer wrapping to 0 when need approaches a value of 0x80000000 (i.e. ~2GB of data), which results in a reallocation of buf->alloc into a small heap chunk.
These integers are declared as size_t in the 2.x branch of yajl, which practically prevents the issue from triggering on 64bit platforms, however this does not preclude this issue triggering on 32bit builds on which size_t is a 32bit integer.
Subsequent population of this under-allocated heap chunk is based on the original buffer size, leading to heap memory corruption.
Patched in yajl-ruby 1.4.3
Workarounds
Avoid passing large inputs to YAJL
References
For more information
If you have any questions or comments about this advisory:
- Open an issue in yajl-ruby
Impact
We rate this as a moderate severity vulnerability which mostly impacts process availability as we believe exploitation for arbitrary code execution to be unlikely.
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-2022-24795 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 (1.4.3); 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-2022-24795? CVE-2022-24795 is a medium-severity integer overflow or wraparound vulnerability in yajl-ruby (rubygems), affecting versions <= 1.4.2. It is fixed in 1.4.3. 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-2022-24795? CVE-2022-24795 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 yajl-ruby are affected by CVE-2022-24795? yajl-ruby (rubygems) versions <= 1.4.2 is affected.
- Is there a fix for CVE-2022-24795? Yes. CVE-2022-24795 is fixed in 1.4.3. Upgrade to this version or later.
- Is CVE-2022-24795 exploitable, and should I be worried? Whether CVE-2022-24795 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-2022-24795 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-2022-24795? Upgrade
yajl-rubyto 1.4.3 or later.