GHSA-9f9p-cp3c-72jf
MEDIUMImproper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') in trillium-http and trillium-client
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
trillium-http🦀trillium-clientReal-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
Summary
Insufficient validation of outbound header values may lead to request splitting or response splitting attacks in scenarios where attackers have sufficient control over outbound headers.
Details
Outbound trillium_http::HeaderValue and trillium_http::HeaderName can be constructed infallibly and were not checked for illegal bytes when sending requests from the client or responses from the server. Thus, if an attacker has sufficient control over header values (or names) in a request or response that they could inject \r\n sequences, they could get the client and server out of sync, and then pivot to gain control over other parts of requests or responses. (i.e. exfiltrating data from other requests, SSRF, etc.)
Patches
trillium-http >= 0.3.12:
- If a header name is invalid in server response headers, the specific header and any associated values are omitted from network transmission.
- If a header value is invalid in server response headers, the individual header value is omitted from network transmission. Other headers values with the same header name will still be sent.
trillium-client >= 0.5.4:
- If any header name or header value is invalid in the client request headers, awaiting the client Conn returns an
Error::MalformedHeaderprior to any network access.
Workarounds
trillium services and client applications should sanitize or validate untrusted input that is included in header values and header names. Carriage return, newline, and null characters are not allowed.
Impact
This only affects use cases where attackers have control of outbound headers, and can insert "\r\n" sequences. Specifically, if untrusted and unvalidated input is inserted into header names or values.
A note on timing from @jbr on behalf of trillium-rs
@divergentdave filed this vulnerability many months ago but I did not see it until the evening of Jan 23, 2024. Patches were issued less than 24h after reading the vulnerability. The security policy has been updated to avoid delays like this in the future.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | trillium-http | all versions | 0.3.12 |
| 🦀crates.io | trillium-client | all versions | 0.5.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for trillium-http. 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 trillium-http to 0.3.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9f9p-cp3c-72jf 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-9f9p-cp3c-72jf 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-9f9p-cp3c-72jf. 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-9f9p-cp3c-72jf in your dependencies?
O3 detects GHSA-9f9p-cp3c-72jf 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.