CVE-2020-25796 — sized-chunks
HIGHCVE-2020-25796 is a high-severity (CVSS 7.5) CWE-129 vulnerability in sized-chunks. 1 public exploit reference exists, so weaponization risk is real. A fix is available for sized-chunks — see the affected versions and patch details below.
Array size is not checked in sized-chunks
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-25796 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
sized-chunksReal-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
An issue was discovered in the sized-chunks crate through 0.6.2 for Rust. In the InlineArray implementation, an unaligned reference may be generated for a type that has a large alignment requirement.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | sized-chunks | all versions | 0.6.3cargo update -p sized-chunks --precise 0.6.3 |
Affected Products
sized-chunkssized-chunks_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sized-chunks, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sized-chunks to 0.6.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-25796 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.
Frequently Asked Questions
Is CVE-2020-25796 in your dependencies?
Find it across crates.io, including transitive dependencies.