Summary
sanic chunked trailer request smuggling allows hidden second request execution
Impact
An attacker who can send a chunked HTTP/1.1 request to a Sanic backend can cause the backend to interpret bytes from the trailer region as a second request on the same keep-alive connection. In the verified proof, that second request was fully routed and executed by the backend even though only one outer request was sent by the client.
This breaks the integrity of HTTP request boundaries inside the server. In real deployments that place Sanic behind reverse proxies, gateways, caches, or other intermediaries, a backend parser mismatch of this kind can become a request smuggling primitive with broader security consequences than the local proof route demonstrates.
CVE-2026-85078 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no 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 (24.12.1, 25.12.1); 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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sanic to 24.12.1 or later; sanic to 25.12.1 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-85078? CVE-2026-85078 is a medium-severity security vulnerability in sanic (pip), affecting versions < 24.12.1. It is fixed in 24.12.1, 25.12.1.
- How severe is CVE-2026-85078? CVE-2026-85078 has a CVSS score of 6.5 (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 versions of sanic are affected by CVE-2026-85078? sanic (pip) versions < 24.12.1 is affected.
- Is there a fix for CVE-2026-85078? Yes. CVE-2026-85078 is fixed in 24.12.1, 25.12.1. Upgrade to this version or later.
- Is CVE-2026-85078 exploitable, and should I be worried? Whether CVE-2026-85078 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-2026-85078 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-2026-85078?
- Upgrade
sanicto 24.12.1 or later - Upgrade
sanicto 25.12.1 or later
- Upgrade