GHSA-4w53-6jvp-gg52
MEDIUMsshpiper's enabling of proxy protocol without proper feature flagging allows faking source address
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
github.com/tg123/sshpiperReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The way the proxy protocol listener is implemented in sshpiper can allow an attacker to forge their connecting address.
Details
This commit added the proxy protocol listener as the only listener in sshpiper, with no option to toggle this functionality off. This means that any connection that sshpiper is directly (or in some cases indirectly) exposed to can use proxy protocol to forge its source address.
PoC
You can use a configuration like this in HAProxy:
listen w-send-proxy
mode tcp
log global
option tcplog
bind *:27654
tcp-request connection set-src ipv4(1.1.1.1)
server app1 ssh-piper-hostname:22 send-proxy
When connecting through HAProxy, sshpiper will log connections as originating from 1.1.1.1. The proxy protocol data is designed to survive multiple load balancers or proxies and pass through to sshpiper at the end, so it should only be enabled trusted environments. This should be behind a configuration option or startup flag to prevent abuse when public connections can be made to sshpiper.
This is also backed up by the specification for proxy protocol:
The receiver MUST be configured to only receive the protocol described in this specification and MUST not try to guess whether the protocol header is present or not. This means that the protocol explicitly prevents port sharing between public and private access. Otherwise it would open a major security breach by allowing untrusted parties to spoof their connection addresses. The receiver SHOULD ensure proper access filtering so that only trusted proxies are allowed to use this protocol.
Impact
Any users of sshpiper who need logs from it for whitelisting/rate limiting/security investigations could have them become much less useful if an attacker is sending a spoofed source address.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/tg123/sshpiper | ≥ 1.0.50&&< 1.3.0 | 1.3.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/tg123/sshpiper. 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 github.com/tg123/sshpiper to 1.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4w53-6jvp-gg52 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-4w53-6jvp-gg52 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-4w53-6jvp-gg52. 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-4w53-6jvp-gg52 in your dependencies?
O3 detects GHSA-4w53-6jvp-gg52 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.