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CRITICAL severity

CVE-2021-28033 — byte_struct

CRITICALFix: wwylele/byte-struct-rs@a535678

CVE-2021-28033 is a critical-severity (CVSS 9.8) CWE-908 vulnerability in byte_struct. A fix is available for byte_struct — see the affected versions and patch details below.

Deserializing an array can free uninitialized memory in byte_struct

Also known asRUSTSEC-2021-0032
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 12, 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 CVEs70th percentile — riskier than 70% of all scored CVEsHighest risk
0.15%0.70%1.25%1.80%0.6%1.3%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-28033 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🦀byte_struct

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

Byte_struct stack and unpack structure as raw bytes with packed or bit field layout. An issue was discovered in the byte_struct crate before 0.6.1 for Rust. There can be a drop of uninitialized memory if a certain deserialization method panics.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iobyte_structall versions0.6.1cargo update -p byte_struct --precise 0.6.1

Affected Products

1 product · 1 configurations
Application
byte structbyte_struct_project
< 0.6.1
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 byte_struct, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update byte_struct to 0.6.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-28033 is resolved across your whole dependency graph.

  3. Workarounds

    Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

Byte_struct stack and unpack structure as raw bytes with packed or bit field layout. An issue was discovered in the byte_struct crate before 0.6.1 for Rust. There can be a drop of uninitialized memory if a certain deserialization method panics.
O3 Security · Impact-Aware SCA

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CVE-2021-28033: byte_struct — Fixed in 0.6.1