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Not in CISA KEV
HIGH severity

CVE-2021-28036 — quinn

HIGH

CVE-2021-28036 is a high-severity (CVSS 7.5) Buffer Overflow vulnerability in quinn. A fix is available for quinn — see the affected versions and patch details below.

quinn invalidly assumes the memory layout of std::net::SocketAddr

Also known asGHSA-fhv4-fx3v-77w6RUSTSEC-2021-0035
Published
Updated
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs69th percentile — riskier than 69% of all scored CVEsHighest risk
0.00%0.58%1.17%1.75%0.3%1.3%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-28036 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

2 pkgs affected
🦀quinn🦀quinn

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

The quinn crate has assumed std::net::SocketAddrV4 and std::net::SocketAddrV6 have the same memory layout as the system C representation sockaddr. It has simply casted the pointers to convert the socket addresses to the system representation. The standard library does not say anything about the memory layout, and this will cause invalid memory access if the standard library changes the implementation. No warnings or errors will be emitted once the change happens.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.ioquinnall versions0.5.4cargo update -p quinn --precise 0.5.4
🦀crates.ioquinn≥ 0.6.0&&< 0.6.20.6.2cargo update -p quinn --precise 0.6.2

Affected Products

1 product · 2 configurations
Application
quinnquinn_project
≥ 0.6.0 && < 0.6.2
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for quinn, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update quinn to 0.5.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-28036 is resolved across your whole dependency graph.

  3. Workarounds

    Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

The quinn crate has assumed std::net::SocketAddrV4 and std::net::SocketAddrV6 have the same memory layout as the system C representation sockaddr. It has simply casted the pointers to convert the socket addresses to the system representation. The standard library does not say anything about the memory layout, and this will cause invalid memory access if the standard library changes the implementation. No warnings or errors will be emitted once the change happens.
O3 Security · Impact-Aware SCA

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CVE-2021-28036: quinn — Fixed in 0.5.4