Summary
Bundled libwebp in pywebp vulnerable
Workarounds
No known workarounds without upgrading.
References
Impact
pywebp versions before v0.3.0 bundled libwebp binaries in wheels that are vulnerable to CVE-2023-4863. The vulnerability was a heap buffer overflow which allowed a remote attacker to perform an out of bounds memory write.
GHSA-F9PM-4G9P-6VM3 has a CVSS score of 8.8 (High). 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 (0.3.0); 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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The problem has been patched upstream in libwebp 1.3.2.
pywebp was updated to bundle a patched version of libwebp in v0.3.0.
Frequently Asked Questions
- What is GHSA-F9PM-4G9P-6VM3? GHSA-F9PM-4G9P-6VM3 is a high-severity security vulnerability in webp (pip), affecting versions < 0.3.0. It is fixed in 0.3.0.
- How severe is GHSA-F9PM-4G9P-6VM3? GHSA-F9PM-4G9P-6VM3 has a CVSS score of 8.8 (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 webp are affected by GHSA-F9PM-4G9P-6VM3? webp (pip) versions < 0.3.0 is affected.
- Is there a fix for GHSA-F9PM-4G9P-6VM3? Yes. GHSA-F9PM-4G9P-6VM3 is fixed in 0.3.0. Upgrade to this version or later.
- Is GHSA-F9PM-4G9P-6VM3 exploitable, and should I be worried? Whether GHSA-F9PM-4G9P-6VM3 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-F9PM-4G9P-6VM3 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-F9PM-4G9P-6VM3? Upgrade
webpto 0.3.0 or later.