Summary
Workarounds
- Do not accept
zserio-encoded messages from non-trusted sources. - Allocate a maximum heap amount to
rust-zerioto avoid impacting other applications.
Impact
When deserializing arrays, strings or bytes (blob) types zserio first reads the size of the variable, and then allocates sufficient memory to load data. Since the size is always trusted this can be abused by creating a data file with a large size value, causing the zserio runtime to allocate large amounts of memory.
GHSA-FPF5-4JW8-67X8 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 (0.5.4); 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.
Remediation advice
Please cherry-pick 57f5fb.
Frequently Asked Questions
- What is GHSA-FPF5-4JW8-67X8? GHSA-FPF5-4JW8-67X8 is a high-severity security vulnerability in rust-zserio (rust), affecting versions <= 0.5.3. It is fixed in 0.5.4.
- How severe is GHSA-FPF5-4JW8-67X8? GHSA-FPF5-4JW8-67X8 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.
- Which versions of rust-zserio are affected by GHSA-FPF5-4JW8-67X8? rust-zserio (rust) versions <= 0.5.3 is affected.
- Is there a fix for GHSA-FPF5-4JW8-67X8? Yes. GHSA-FPF5-4JW8-67X8 is fixed in 0.5.4. Upgrade to this version or later.
- Is GHSA-FPF5-4JW8-67X8 exploitable, and should I be worried? Whether GHSA-FPF5-4JW8-67X8 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 GHSA-FPF5-4JW8-67X8 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 GHSA-FPF5-4JW8-67X8? Upgrade
rust-zserioto 0.5.4 or later.