RUSTSEC-2026-0204: Invalid pointer dereference in `fmt::Pointer` impl for `Atomic` and `Shared` when the underlying pointer is invalid

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
45/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Quiet
Tech stack
rust
Domain
security

Research direction

The issue identifies crossbeam-epoch 0.9.18 as affected and 0.9.20 as patched, but names no repository file or test. Review the project's dependency declarations and lockfile, then verify that no vulnerable version remains and that the existing checks pass.

Written by the indexing model from the issue text.

Description

Invalid pointer dereference in fmt::Pointer impl for Atomic and Shared when the underlying pointer is invalid

Details
Package crossbeam-epoch
Version 0.9.18
URL https://github.com/crossbeam-rs/crossbeam/pull/1276
Date 2026-07-06
Patched versions >=0.9.20
Unaffected versions <0.9.0

Affected versions of fmt::Display dereference the underlying pointer. This causes a invalid pointer dereference e.g., when a pointer created with Atomic::null or Shared::null. fmt::Debug impls and pre-0.9 fmt::Display impls, which do not dereference pointers, are not affected by this issue.

See advisory page for additional details.

Dominant language
Rust
Stars
13
Forks
5
Avg merge
8d 10h
Merged PRs (30d)
13

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