CVE-2026-10740
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 · uneditedUnbounded memory allocation in the CRYPTO frame reassembler in s2n-quic before 1.8.2 may allow an unauthenticated remote actor to cause a denial of service (degraded availability) by sending crafted QUIC Initial packets. To remediate this issue, users should upgrade to v1.8.2.
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 · high confidences2n-quic before v1.8.2 contains an unbounded memory allocation vulnerability in its CRYPTO frame reassembler. An unauthenticated remote attacker can send specially crafted QUIC Initial packets with malformed CRYPTO frames, causing excessive memory allocation and leading to degraded availability or denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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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Locate s2n-quic library in your environmentSearch for s2n-quic in your dependency manifests (e.g., package.json, Cargo.toml, requirements.txt, pom.xml, go.mod) or list installed packages that include 's2n-quic'Affected if s2n-quic is present as a dependency or installed package
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Determine installed s2n-quic versionRun your package manager's version query command (e.g., cargo tree -p s2n-quic, npm list s2n-quic, pip show s2n-quic) or inspect the lock file for the s2n-quic version entryAffected if The version is lower than v1.8.2 or the version cannot be determined (indicating an outdated release)
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Verify if QUIC server functionality is enabledReview your application code or configuration for s2n-quic server initialization (look for Server::new, quic::Server, or similar QUIC listener creation)Affected if Your application creates a QUIC listener or accepts incoming QUIC connections using s2n-quic
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Confirm CRYPTO frame processing is activeCheck that your s2n-quic endpoint is configured to handle Initial packets (default behavior for QUIC servers). Inspect logs or metrics for incoming QUIC connection attemptsAffected if The endpoint accepts or processes incoming QUIC Initial packets from clients
You are affected if s2n-quic version is below v1.8.2 AND your application runs as a QUIC server or client that processes CRYPTO frames in QUIC Initial packets.
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.
dbcve · scopedUpgrade s2n-quic to v1.8.2 or later to remediate the unbounded memory allocation vulnerability. No additional configuration changes are required beyond the library upgrade.
v1.8.2
- Upgrade s2n-quic to version 1.8.2 or later
- Verify the upgrade by checking the installed version matches or exceeds v1.8.2
- Test the upgrade in a staging environment before deploying to production
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-10740 — 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-2026-10740 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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