How severe is CVE-2024-40640?

CVE-2024-40640 has a CVSS score of 2.9/10, rated LOW. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2024-40640?

CVE-2024-40640 affects the following packages: vodozemac (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2024-40640?

Update vodozemac to 0.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-40640 is resolved across your whole dependency graph.

How do I detect CVE-2024-40640 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vodozemac. 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.

How do I mitigate CVE-2024-40640 if there is no patch (or I can't update yet)?

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 does O3 Security protect against CVE-2024-40640?

O3 pinpoints whether CVE-2024-40640 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2024-40640 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-40640 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-40640?

CVE-2024-40640 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 10th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2024-40640 published, and has it been updated?

CVE-2024-40640 was published on July 17, 2024 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2024-40640: vodozemac (Low 2.9)

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk10th percentile+0.10%

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.

Blast Radius

1 pkg affected

🦀vodozemac

Real-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

vodozemac is an open source implementation of Olm and Megolm in pure Rust. Versions before 0.7.0 of vodozemac use a non-constant time base64 implementation for importing key material for Megolm group sessions and PkDecryption Ed25519 secret keys. This flaw might allow an attacker to infer some information about the secret key material through a side-channel attack. The use of a non-constant time base64 implementation might allow an attacker to observe timing variations in the encoding and decoding operations of the secret key material. This could potentially provide insights into the underlying secret key material. The impact of this vulnerability is considered low because exploiting the attacker is required to have access to high precision timing measurements, as well as repeated access to the base64 encoding or decoding processes. Additionally, the estimated leakage amount is bounded and low according to the referenced paper. This has been patched in commit 734b6c6948d4b2bdee3dd8b4efa591d93a61d272 which has been included in release version 0.7.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`vodozemac`	all versions	0.7.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vodozemac. 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 vodozemac to 0.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-40640 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-2024-40640 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-2024-40640. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

vodozemac is an open source implementation of Olm and Megolm in pure Rust. Versions before 0.7.0 of vodozemac use a non-constant time base64 implementation for importing key material for Megolm group sessions and `PkDecryption` Ed25519 secret keys. This flaw might allow an attacker to infer some information about the secret key material through a side-channel attack. The use of a non-constant time base64 implementation might allow an attacker to observe timing variations in the encoding and decoding operations of the secret key material. This could potentially provide insights into the underl

O3 Security · Impact-Aware SCA

Is CVE-2024-40640 in your dependencies?

O3 detects CVE-2024-40640 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.

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CVE-2024-40640