GHSA-jpv7-p47h-f43j
letmein connection limiter allows an arbitrary amount of simultaneous connections
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
letmeind🦀letmeinfwdReal-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
The connection limiter is implemented incorrectly.
It allows an arbitrary amount of simultaneously incoming connections (TCP, UDP and Unix socket) for the services letmeind and letmeinfwd.
Therefore, the command line option num-connections is not effective and does not limit the number of simultaneously incoming connections.
letmeind is the public network facing daemon (TCP/UDP).
letmeinfwd is the internal firewall daemon that only listens on local Unix socket.
Possible Denial Of Service by resource exhaustion.
Affected versions
All versions <= 10.2.0 are affected.
Patches
All users shall upgrade to version 10.2.1.
Workarounds
Untested possible workarounds:
- It might be possible to limit the number of active connections to the
letmeindport (default 5800) via firewall. - The resource consumption of the service might be restricted with a service manager such as systemd.
Severity:
If a (D)DoS is run against the service, something is going to be affected. The connection limiter assures that the effect on the system itself is limited at the expense of the effect on the letmein services itself. So even with the connection limiter active, a (D)DoS can lead to a less responsive or unresponsive letmein service.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | letmeind | all versions | 10.2.1 |
| 🦀crates.io | letmeinfwd | all versions | 10.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for letmeind. 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 letmeind to 10.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jpv7-p47h-f43j 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-jpv7-p47h-f43j 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-jpv7-p47h-f43j. 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-jpv7-p47h-f43j in your dependencies?
O3 detects GHSA-jpv7-p47h-f43j 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.