GHSA-6V7P-G79W-8964 is a high-severity use after free vulnerability in msgpack (pip), affecting versions <= 1.2.0. It is fixed in 1.2.1.
Impact If the Unpacker is used repeatedly after an error occurs, the process may crash with a SEGV. If the Unpacker is used repeatedly to unpack untrusted input from external sources, it may be vulnerable to a DoS attack. Patches v1.2.1 Workarounds Users should create a new Unpacker instead of reusing the same Unpacker after an error occurs. Applying the above patch can prevent SEGV, but reusing the Streaming Unpacker after it has encountered an error will not yield correct data. If an error occurs during Streaming Unpacking, the Stream and Streaming Unpacker should be discarded. Therefore, this is not just a workaround but the correct solution. The above patch only prevents crashes from incorrect usage.
Memory is accessed after it has been freed, leading to undefined behavior in native code. Typical impact: memory corruption, crash, or potential code execution.
GHSA-6V7P-G79W-8964 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 (1.2.1). Upgrading removes the vulnerable code path.
pip
msgpack (<= 1.2.0)msgpack → 1.2.1 (pip)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 instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether GHSA-6V7P-G79W-8964 is reachable in your applications. Explore open-source security for your team.
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Already deployed Kodem? See GHSA-6V7P-G79W-8964 in your environment →Upgrade msgpack to 1.2.1 or later to resolve this vulnerability.
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GHSA-6V7P-G79W-8964 is a high-severity use after free vulnerability in msgpack (pip), affecting versions <= 1.2.0. It is fixed in 1.2.1. Memory is accessed after it has been freed, leading to undefined behavior in native code.
GHSA-6V7P-G79W-8964 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.
msgpack (pip) versions <= 1.2.0 is affected.
Yes. GHSA-6V7P-G79W-8964 is fixed in 1.2.1. Upgrade to this version or later.
Whether GHSA-6V7P-G79W-8964 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
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.
Upgrade msgpack to 1.2.1 or later.