Summary
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') in trillium-http and trillium-client
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.)
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.
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.
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.
CVE-2024-23644 has a CVSS score of 6.8 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.3.12, 0.5.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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trillium-http to 0.3.12 or later; trillium-client to 0.5.4 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2024-23644? CVE-2024-23644 is a medium-severity security vulnerability in trillium-http (rust), affecting versions < 0.3.12. It is fixed in 0.3.12, 0.5.4.
- How severe is CVE-2024-23644? CVE-2024-23644 has a CVSS score of 6.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which packages are affected by CVE-2024-23644?
trillium-http(rust) (versions < 0.3.12)trillium-client(rust) (versions < 0.5.4)
- Is there a fix for CVE-2024-23644? Yes. CVE-2024-23644 is fixed in 0.3.12, 0.5.4. Upgrade to this version or later.
- Is CVE-2024-23644 exploitable, and should I be worried? Whether CVE-2024-23644 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2024-23644 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2024-23644?
- Upgrade
trillium-httpto 0.3.12 or later - Upgrade
trillium-clientto 0.5.4 or later
- Upgrade