CVE-2023-43635
HIGHCVE-2023-43635 is a high-severity (CVSS 8.8) CWE-328 vulnerability in github.com/lf-edge/eve. O3 Security confirms whether CVE-2023-43635 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Vault Key Sealed With SHA1 PCRs
Blast Radius
github.com/lf-edge/eveReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Vault Key Sealed With SHA1 PCRs
The measured boot solution implemented in EVE OS leans on a PCR locking mechanism.
Different parts of the system update different PCR values in the TPM, resulting in a unique value for each PCR entry.
These PCRs are then used in order to seal/unseal a key from the TPM which is used to encrypt/decrypt the “vault” directory.
This “vault” directory is the most sensitive point in the system and as such, its content should be protected.
This mechanism is noted in Zededa’s documentation as the “measured boot” mechanism, designed to protect said “vault”.
The code that’s responsible for generating and fetching the key from the TPM assumes that SHA256 PCRs are used in order to seal/unseal the key, and as such their presence is being checked.
The issue here is that the key is not sealed using SHA256 PCRs, but using SHA1 PCRs. This leads to several issues:
• Machines that have their SHA256 PCRs enabled but SHA1 PCRs disabled, as well as not sealing their keys at all, meaning the “vault” is not protected from an attacker.
• SHA1 is considered insecure and reduces the complexity level required to unseal the key in machines which have their SHA1 PCRs enabled.
An attacker can very easily retrieve the contents of the “vault”, which will effectively render the “measured boot” mechanism meaningless.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/lf-edge/eve | all versions | 0.0.0-20230519072751-977f42b07fa9 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lf-edge/eve. 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 github.com/lf-edge/eve to 0.0.0-20230519072751-977f42b07fa9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-43635 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-2023-43635 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-2023-43635. 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-2023-43635 in your dependencies?
O3 detects CVE-2023-43635 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.