GHSA-rcx8-48pc-v9q8 — mail-internals
GHSA-rcx8-48pc-v9q8 is a security vulnerability in mail-internals. No vendor fix is recorded yet; mitigation options are listed below.
mail-internals use-after-free vulnerability in `vec_insert_bytes`
Real-World Exposure
mail-internalsReal-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
Incorrect reallocation logic in the function vec_insert_bytes causes a use-after-free.
This function does not have to be called directly to trigger the vulnerability because many methods on EncodingWriter call this function internally.
The mail-* suite is unmaintained and the upstream sources have been actively vandalised.
A fixed mail-internals-ng (and mail-headers-ng and mail-core-ng) crate has been published which fixes this, and a dependency on another unsound crate.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | mail-internals | ≥ 0.2.0 | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mail-internals, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of mail-internals has shipped for GHSA-rcx8-48pc-v9q8 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-rcx8-48pc-v9q8 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-rcx8-48pc-v9q8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-rcx8-48pc-v9q8 in your dependencies?
O3 Security finds GHSA-rcx8-48pc-v9q8 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.