CVE-2018-20995
CRITICALCVE-2018-20995 is a critical-severity (CVSS 9.8) Buffer Overflow vulnerability in slice-deque. O3 Security confirms whether CVE-2018-20995 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Memory corruption slice-deque
Real-World Exposure
slice-dequeReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Affected versions of this crate did not properly update the head and tail of the deque when inserting and removing elements from the front if, before insertion or removal, the tail of the deque was in the mirrored memory region, and if, after insertion or removal, the head of the deque is exactly at the beginning of the mirrored memory region.
An attacker that controls both element insertion and removal into the deque could put it in a corrupted state. Once the deque enters such an state, its head and tail are corrupted, but in bounds of the allocated memory. This can result in partial reads and writes, reads of uninitialized memory, reads of memory containing previously dropped objects, etc. An attacker could exploit this to alter program execution.
The flaw was corrected by properly updating the head and tail of the deque in this case.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | slice-deque | all versions | 0.1.16 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for slice-deque. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update slice-deque to 0.1.16 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-20995 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2018-20995 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2018-20995. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2018-20995 in your dependencies?
O3 detects CVE-2018-20995 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.