CVE-2021-25900Critical· 9.8▾ MidnightBuffer overflow in SmallVec::insert_many
▾ Midnight zone — Critical, or high with PoC / in-the-wild
impact 53.9 · likelihood 0.3 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 17.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
1.7%
A bug in the SmallVec::insert_many method caused it to allocate a buffer that was smaller than needed. It then wrote past the end of the buffer, causing a buffer overflow and memory corruption on the heap.
This bug was only triggered if the iterator passed to insert_many yielded more items than the lower bound returned from its size_hint method.
The flaw was corrected in smallvec 0.6.14 and 1.6.1, by ensuring that additional space is always reserved for each item inserted. The fix also simplified the implementation of insert_many to use less unsafe code, so it is easier to verify its correctness.
Thank you to Yechan Bae (@Qwaz) and the Rust group at Georgia Tech’s SSLab for finding and reporting this bug.
smallvec >= 1.0.0, < 1.6.1Upgrade to a patched release:
smallvec 1.6.1Connected by shared product, vendor, weakness, or advisory.
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CVE-2018-20991Critical· 9.8Possible double free during unwinding in SmallVec::insert_many