CVE-2020-35908
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue was discovered in the futures-util crate before 0.3.2 for Rust. FuturesUnordered can lead to data corruption because Sync is mishandled.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThe FuturesUnordered type in the futures-util crate before v0.3.2 incorrectly implements the Sync trait, allowing data to be accessed from multiple threads unsafely. This mishandling can lead to data corruption when FuturesUnordered is shared across threads, as the internal synchronization is insufficient for safe concurrent access.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 0.3.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify futures-util as a dependencyReview your project's Cargo.toml and any Cargo.lock file to determine if the futures-util crate is listed as a direct or transitive dependencyAffected if futures-util appears as a dependency in the project
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Determine the installed futures-util versionCheck the version number specified next to futures-util in Cargo.lock, or run 'cargo tree -p futures-util' to see the exact version being usedAffected if the version is below 0.3.2 (e.g., 0.3.0, 0.3.1, etc.)
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Locate FuturesUnordered usage in codebaseSearch source code for any instances of 'FuturesUnordered' being instantiated or used, particularly in modules dealing with asynchronous operationsAffected if FuturesUnordered is used anywhere in the codebase
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Check if FuturesUnordered is shared across threadsExamine whether FuturesUnordered instances are wrapped in Arc, shared via channel sends across thread boundaries, or otherwise accessed from multiple threads (look for Arc<FuturesUnordered<T>> or similar patterns)Affected if FuturesUnordered is accessed from multiple threads simultaneously
You are affected if your project uses futures-util version below 0.3.2 AND uses FuturesUnordered in a concurrent context where it is shared across threads.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data0.3.2
Update the futures-util crate to version 0.3.2 or later to obtain the correct Sync implementation. Audit dependent crates to ensure the updated version is pulled in and test concurrent FuturesUnordered usage thoroughly.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-35908 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-35908 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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