CVE-2023-26049

Nonstandard cookie parsing in Jetty may allow an attacker to smuggle cookies within other cookies, or otherwise perform unintended behavior by tampering with the cookie parsing mechanism.

If Jetty sees a cookie VALUE that starts with " (double quote), it will continue to read the cookie string until it sees a closing quote -- even if a semicolon is encountered.

So, a cookie header such as:

DISPLAY_LANGUAGE="b; JSESSIONID=1337; c=d" will be parsed as one cookie, with the name DISPLAY_LANGUAGE and a value of b; JSESSIONID=1337; c=d

instead of 3 separate cookies.

Workarounds

No workarounds

References

• https://www.rfc-editor.org/rfc/rfc2965
• https://www.rfc-editor.org/rfc/rfc6265

This has security implications because if, say, JSESSIONID is an HttpOnly cookie, and the DISPLAY_LANGUAGE cookie value is rendered on the page, an attacker can smuggle the JSESSIONID cookie into the DISPLAY_LANGUAGE cookie and thereby exfiltrate it. This is significant when an intermediary is enacting some policy based on cookies, so a smuggled cookie can bypass that policy yet still be seen by the Jetty server.

CVE-2023-26049 has a CVSS score of 2.4 (Low). The vector is network-reachable, high privileges required, and user interaction required. 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 (10.0.14, 11.0.14, 12.0.0.beta0, 9.4.51.v20230217); upgrading removes the vulnerable code path.

Kodem intelligence

• 9.4.51.v20230217 - via PR #9352
• 10.0.15 - via PR #9339
• 11.0.15 - via PR #9339

1. What is CVE-2023-26049? CVE-2023-26049 is a low-severity security vulnerability in org.eclipse.jetty:jetty-server (maven), affecting versions >= 10.0.0, < 10.0.14. It is fixed in 10.0.14, 11.0.14, 12.0.0.beta0, 9.4.51.v20230217.
2. How severe is CVE-2023-26049? CVE-2023-26049 has a CVSS score of 2.4 (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.
3. Which versions of org.eclipse.jetty:jetty-server are affected by CVE-2023-26049? org.eclipse.jetty:jetty-server (maven) versions >= 10.0.0, < 10.0.14 is affected.
4. Is there a fix for CVE-2023-26049? Yes. CVE-2023-26049 is fixed in 10.0.14, 11.0.14, 12.0.0.beta0, 9.4.51.v20230217. Upgrade to this version or later.
5. Is CVE-2023-26049 exploitable, and should I be worried? Whether CVE-2023-26049 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
6. What actually determines whether CVE-2023-26049 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.
7. How do I fix CVE-2023-26049?
   • Upgrade org.eclipse.jetty:jetty-server to 10.0.14 or later
   • Upgrade org.eclipse.jetty:jetty-server to 11.0.14 or later
   • Upgrade org.eclipse.jetty:jetty-server to 12.0.0.beta0 or later
   • Upgrade org.eclipse.jetty:jetty-server to 9.4.51.v20230217 or later