CVE-2023-45288

An attacker may cause an HTTP/2 endpoint to read arbitrary amounts of header data by sending an excessive number of CONTINUATION frames. Maintaining HPACK state requires parsing and processing all HEADERS and CONTINUATION frames on a connection. When a request's headers exceed MaxHeaderBytes, no memory is allocated to store the excess headers, but they are still parsed. This permits an attacker to cause an HTTP/2 endpoint to read arbitrary amounts of header data, all associated with a request which is going to be rejected. These headers can include Huffman-encoded data which is significantly more expensive for the receiver to decode than for an attacker to send. The fix sets a limit on the amount of excess header frames we will process before closing a connection.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2023-45288 has a CVSS score of 5.3 (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 (1.21.9, 0.23.0, 1.22.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2023-45288? CVE-2023-45288 is a medium-severity uncontrolled resource consumption vulnerability in net/http (go), affecting versions < 1.21.9. It is fixed in 1.21.9, 0.23.0, 1.22.2. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2023-45288? CVE-2023-45288 has a CVSS score of 5.3 (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.
3. Which packages are affected by CVE-2023-45288?
   • net/http (go) (versions < 1.21.9)
   • golang.org/x/net/http2 (go) (versions < 0.23.0)
   • golang.org/x/net (go) (versions < 0.23.0)
4. Is there a fix for CVE-2023-45288? Yes. CVE-2023-45288 is fixed in 1.21.9, 0.23.0, 1.22.2. Upgrade to this version or later.
5. Is CVE-2023-45288 exploitable, and should I be worried? Whether CVE-2023-45288 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-2023-45288 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-2023-45288?
   • Upgrade net/http to 1.21.9 or later
   • Upgrade golang.org/x/net/http2 to 0.23.0 or later
   • Upgrade net/http to 1.22.2 or later
   • Upgrade golang.org/x/net to 0.23.0 or later