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Fencer Intel
high —

GHSA-9c9f-7x9p-4wqp json

A malicious coder can get unsound access to TCell or TLCell memory

published 4y ago modified 3y ago also RUSTSEC-2022-0007

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
—
no score, EPSS covers CVEs only
public exploits
0
none known

Summary

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.

Patch / fix

  • crates.io qcell 0.4.3

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Affected packages

ecosystem package affected fixed in
crates.io qcell
<0.4.3
>=0.0.0-0, <0.4.3
0.4.3

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.