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GHSA-r24f-hg58-vfrw unsafe-libyaml

Fix: dtolnay/unsafe-libyaml@7755559

GHSA-r24f-hg58-vfrw is a security vulnerability in unsafe-libyaml. A fix is available for unsafe-libyaml — see the affected versions and patch details below.

unsafe-libyaml unaligned write of u64 on 32-bit and 16-bit platforms

Also known asRUSTSEC-2023-0075
Published
Dec 21, 2023
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 10, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🦀unsafe-libyaml

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

Affected versions allocate memory using the alignment of usize and write data to it of type u64, without using core::ptr::write_unaligned. In platforms with sub-64bit alignment for usize (including wasm32 and x86) these writes are insufficiently aligned some of the time.

If using an ordinary optimized standard library, the bug exhibits Undefined Behavior so may or may not behave in any sensible way, depending on optimization settings and hardware and other things. If using a Rust standard library built with debug assertions enabled, the bug manifests deterministically in a crash (non-unwinding panic) saying "ptr::write requires that the pointer argument is aligned and non-null".

No 64-bit platform is impacted by the bug.

The flaw was corrected by allocating with adequately high alignment on all platforms.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🦀crates.iounsafe-libyamlall versions0.2.10cargo update -p unsafe-libyaml --precise 0.2.10

Detection & mitigation playbook

Open-source dependency
  1. Detect

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

  2. Fix

    Update unsafe-libyaml to 0.2.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r24f-hg58-vfrw is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-r24f-hg58-vfrw can be triaged on real exposure rather than presence alone.

Tailored to GHSA-r24f-hg58-vfrw. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Affected versions allocate memory using the alignment of `usize` and write data to it of type `u64`, without using `core::ptr::write_unaligned`. In platforms with sub-64bit alignment for `usize` (including wasm32 and x86) these writes are insufficiently aligned some of the time. If using an ordinary optimized standard library, the bug exhibits Undefined Behavior so may or may not behave in any sensible way, depending on optimization settings and hardware and other things. If using a Rust standard library built with debug assertions enabled, the bug manifests deterministically in a crash (non-
O3 Security · Impact-Aware SCA

Is GHSA-r24f-hg58-vfrw in your dependencies?

O3 Security finds GHSA-r24f-hg58-vfrw across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-r24f-hg58-vfrw: unsafe-libyaml | O3 Security