CVE-2023-45288 — http
MEDIUMCVE-2023-45288 is a medium-severity (CVSS 5.3) vulnerability in net/http. 2 public exploit references exist, so weaponization risk is real. A fix is available for net/http — see the affected versions and patch details below.
net/http, x/net/http2: close connections when receiving too many headers
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-45288.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2023-45288 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 397,508 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
net/http🐹golang.org/x/net/http2🐹net/http🐹golang.org/x/netReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | net/http | all versions | 1.21.9go get net/http@v1.21.9 |
| 🐹Go | golang.org/x/net/http2 | all versions | 0.23.0go get golang.org/x/net/http2@v0.23.0 |
| 🐹Go | net/http | ≥ 1.22.0-0&&< 1.22.2 | 1.22.2go get net/http@v1.22.2 |
| 🐹Go | golang.org/x/net | all versions | 0.23.0go get golang.org/x/net@v0.23.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for net/http, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update net/http to 1.21.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-45288 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat rates the security impact of this vulnerability as Important due to the worst case scenario resulting in a denial of service. It is simple to exploit, could significantly impact availability, and there is not a suitable mitigation for all use cases. Once an attack has ended, the system should return to normal…
In some environments where http/2 support is not required, it may be possible to disable this feature to reduce risk.Source: Red Hat security advisory for CVE-2023-45288 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Builds for Red Hat OpenShift | openshift-builds-operator-container | RHSA-2024:6221 |
| Cryostat 2 on RHEL 8 | cryostat-tech-preview/cryostat-grafana-dashboard-rhel8:2.4.0-7 | RHSA-2024:2088 |
| LVMS-4.13-RHEL-8 | lvms4/lvms-must-gather-rhel8:v4.13.6-2 | RHBA-2024:2648 |
| LVMS-4.14-RHEL-9 | lvms4/lvms-must-gather-rhel9:v4.14.5-2 | RHBA-2024:2646 |
| MTA-7.0-RHEL-9 | mta/mta-cli-rhel9:7.0.3-16 | RHSA-2024:3316 |
| OADP-1.3-RHEL-9 | oadp/oadp-rhel9-operator:1.3.3-12 | RHSA-2024:4982 |
| OpenShift Custom Metrics Autoscaler 2 | custom-metrics-autoscaler/custom-metrics-autoscaler-adapter-rhel8:2.12.1-394 | RHSA-2024:2901 |
| OpenShift-Pipelines-1.15-RHEL-8 | openshift-pipelines-client-0:1.15.0-11496.el8 | RHEA-2024:4022 |
Frequently Asked Questions
Is CVE-2023-45288 in your dependencies?
Find it across Go, including transitive dependencies.