CVE-2021-21235
MEDIUMCVE-2021-21235 is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in kamadak-exif. O3 Security confirms whether CVE-2021-21235 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
kamadak-exif vulnerable to Infinite loop when parsing PNG files
Blast Radius
kamadak-exifReal-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
kamadak-exif is an exif parsing library written in pure Rust. In kamadak-exif version 0.5.2, there is an infinite loop in parsing crafted PNG files. Specifically, reader::read_from_container can cause an infinite loop when a crafted PNG file is given. This is fixed in version 0.5.3. No workaround is available. Applications that do not pass files with the PNG signature to Reader::read_from_container are not affected.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | kamadak-exif | ≥ 0.5.2&&< 0.5.3 | 0.5.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kamadak-exif. 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 kamadak-exif to 0.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21235 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-2021-21235 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-2021-21235. 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-2021-21235 in your dependencies?
O3 detects CVE-2021-21235 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.