GHSA-vc2p-r46x-m3vx
MEDIUMArgument injection in lettre
Blast Radius
lettre🦀lettre🦀lettreReal-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
Impact
Affected versions of lettre allowed argument injection to the sendmail command. It was possible, using forged to addresses, to pass arbitrary arguments to the sendmail executable.
Depending on the implementation (original sendmail, postfix, exim, etc.) it could be possible in some cases to write email data into abritrary files (using sendmail's logging features).
NOTE: This vulnerability only affects the sendmail transport. Others, including smtp, are not affected.
Fix
The flaw is corrected by modifying the executed command to stop parsing arguments before passing the destination addresses.
References
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | lettre | ≥ 0.9.0&&< 0.9.5 | 0.9.5 |
| 🦀crates.io | lettre | ≥ 0.8.0&&< 0.8.4 | 0.8.4 |
| 🦀crates.io | lettre | ≥ 0.7.0&&< 0.7.1 | 0.7.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for lettre. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update lettre to 0.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vc2p-r46x-m3vx is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether GHSA-vc2p-r46x-m3vx is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-vc2p-r46x-m3vx. 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-vc2p-r46x-m3vx in your dependencies?
O3 detects GHSA-vc2p-r46x-m3vx across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.