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The vulnerability in `id_map::IdMap::from_iter` arises due to incorrect memory handling when constructing an `IdMap` from an iterator. The constructor initializes the `ids` field based on the capacity of the `values` vector, which is built from the provided iterator. However, if the iterator produces fewer items than the vector’s capacity, the `values` vector’s length remains smaller than its capacity. When the `IdMap` is dropped, its destructor assumes `values.capacity()` elements are initialized and attempts to drop them, leading to the freeing of uninitialized memory. This causes undefined behavior, including potential segmentation faults. The issue was resolved by removing unsafe code in commit fab6922.
DailyCVE Form:
Platform: Rust `id_map` crate
Version: Pre-fab6922
Vulnerability: Memory corruption
Severity: Moderate
Date: Aug 18, 2025
Prediction: Patch expected Aug 25, 2025
What Undercode Say:
// Example vulnerable usage let map = id_map::IdMap::from_iter((0..10).filter(|x| x % 2 == 0));
How Exploit:
- Craft iterator with fewer items than capacity
- Trigger drop to free uninitialized memory
- Cause segmentation fault
Protection from this CVE:
- Update to post-fab6922
- Avoid custom unsafe iterators
- Use recommended alternatives
Impact:
- Undefined behavior
- Potential crashes
- Memory corruption
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Sources:
Reported By: github.com
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