Summary
BoringSSLAEADContext in Netty Repeats Nonces
BoringSSLAEADContext keeps track of how many OHTTP responses have been sent and uses this sequence number to calculate the appropriate nonce to use with the encryption algorithm.
Unfortunately, two separate errors combine which would allow an attacker to cause the sequence number to overflow and thus the nonce to repeat.
Details
- There is no overflow detection or enforcement of the maximum sequence value. (This is a missed requirement from the draft Chunked Oblivious OHTTP RFC and so should be inherited from the HPKE RFC 9180, Section 5.2).
- The sequence number (seq) is stored as 32-bit int which is relatively easy to overflow.
Impact
If the BoringSSLAEADContext is used to encrypt more than 2^32 messages then the AES-GCM nonce will repeat.
Repeating a nonce with AES-GCM results in both confidentiality and integrity compromise of data encrypted with the associated key.
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-2024-36121 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and user interaction required. 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 (0.0.11.Final); 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-2024-36121? CVE-2024-36121 is a medium-severity integer overflow or wraparound vulnerability in io.netty.incubator:netty-incubator-codec-ohttp (maven), affecting versions >= 0.0.3.Final, < 0.0.11.Final. It is fixed in 0.0.11.Final. 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-2024-36121? CVE-2024-36121 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 io.netty.incubator:netty-incubator-codec-ohttp are affected by CVE-2024-36121? io.netty.incubator:netty-incubator-codec-ohttp (maven) versions >= 0.0.3.Final, < 0.0.11.Final is affected.
- Is there a fix for CVE-2024-36121? Yes. CVE-2024-36121 is fixed in 0.0.11.Final. Upgrade to this version or later.
- Is CVE-2024-36121 exploitable, and should I be worried? Whether CVE-2024-36121 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-2024-36121 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-2024-36121? Upgrade
io.netty.incubator:netty-incubator-codec-ohttpto 0.0.11.Final or later.