Summary
A malicious coder can get unsound access to TCell or TLCell memory
This is impossible to do by accident, but by carefully constructing
marker types to be covariant, a malicious coder can cheat the
singleton check in TCellOwner and TLCellOwner, giving unsound
access to cell memory. This could take the form of getting two
mutable references to the same memory, or a mutable reference and an
immutable reference.
The fix is for the crate to internally force the marker type to be
invariant. This blocks the conversion between covariant types which
Rust normally allows.
Impact
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 GHSA-9C9F-7X9P-4WQP? GHSA-9C9F-7X9P-4WQP is a high-severity security vulnerability in qcell (rust), affecting versions < 0.4.3. It is fixed in 0.4.3.
- Which versions of qcell are affected by GHSA-9C9F-7X9P-4WQP? qcell (rust) versions < 0.4.3 is affected.
- Is there a fix for GHSA-9C9F-7X9P-4WQP? Yes. GHSA-9C9F-7X9P-4WQP is fixed in 0.4.3. Upgrade to this version or later.
- Is GHSA-9C9F-7X9P-4WQP exploitable, and should I be worried? Whether GHSA-9C9F-7X9P-4WQP 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-9C9F-7X9P-4WQP 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-9C9F-7X9P-4WQP? Upgrade
qcellto 0.4.3 or later.