CVE-2026-41678 — openssl
Fix: rust-openssl/rust-openssl#2604CVE-2026-41678 is a Out-of-bounds Write vulnerability in openssl. A fix is available for openssl — see the affected versions and patch details below.
rust-openssl: Incorrect bounds assertion in aes key wrap
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-41678.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
opensslReal-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
Summary
aes::unwrap_key() has an incorrect bounds assertion on the out buffer size, which can lead to out-of-bounds write.
Details
aes::unwrap_key() contains an incorrect assertion: it checks that out.len() + 8 <= in_.len(), but this condition is reversed. The intended invariant is out.len() >= in_.len() - 8, ensuring the output buffer is large enough.
Because of the inverted check, the function only accepts buffers at or below the minimum required size and rejects larger ones. If a smaller buffer is provided the function will write past the end of out by in_.len() - 8 - out.len() bytes, causing an out-of-bounds write from a safe public function.
Impact
Vulnerable applications using AES keywrap and allowing attacker controlled buffer sizes could have an attacker trigger an out-of-bounds write.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | openssl | ≥ 0.10.24&&< 0.10.78 | 0.10.78cargo update -p openssl --precise 0.10.78 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openssl, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update openssl to 0.10.78 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-41678 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-41678 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-41678. 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-2026-41678 in your dependencies?
O3 Security finds CVE-2026-41678 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.