CVE-2026-6733 is a low-severity security vulnerability in undici (npm), affecting versions < 6.27.0. It is fixed in 6.27.0, 7.28.0, 8.5.0.
Impact Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. Patches Upgrade to undici v6.27.0, v7.28.0 or v8.5.0. Workarounds Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.
CVE-2026-6733 has a CVSS score of 3.7 (Low). 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 (6.27.0, 7.28.0, 8.5.0). Upgrading removes the vulnerable code path.
npm
undici (< 6.27.0)undici (>= 7.0.0, < 7.28.0)undici (>= 8.0.0, < 8.5.0)undici → 6.27.0 (npm)undici → 7.28.0 (npm)undici → 8.5.0 (npm)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 instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-6733 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-6733 is reachable in your applications. Get a demo
Upgrade the following packages to resolve this vulnerability:
undici to 6.27.0 or laterundici to 7.28.0 or laterundici to 8.5.0 or laterKodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-6733 is a low-severity security vulnerability in undici (npm), affecting versions < 6.27.0. It is fixed in 6.27.0, 7.28.0, 8.5.0.
CVE-2026-6733 has a CVSS score of 3.7 (Low). 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.
undici (npm) versions < 6.27.0 is affected.
Yes. CVE-2026-6733 is fixed in 6.27.0, 7.28.0, 8.5.0. Upgrade to this version or later.
Whether CVE-2026-6733 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
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.
undici to 6.27.0 or laterundici to 7.28.0 or laterundici to 8.5.0 or later