CVE-2023-45288 | HTTP/2 CONTINUATION flood in net/http

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.

Published: 2024-04-04 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-45288 is rated High Risk (69.6/100): CVSS High severity, with high exploitation likelihood (EPSS 75.27%, 99th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +5.36% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-45288

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-03 69.91% 75.27% +5.36%
2 2026-05-26 64.85% 69.91% +5.05%
3 2026-05-22 64.85%

Full EPSS history (56 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-45288

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-45288

GitHub Security Advisory for CVE-2023-45288

GHSA-4v7x-pqxf-cx7m · Severity: medium · Ecosystem: go — net/http, x/net/http2: close connections when receiving too many headers

OS Trackers for CVE-2023-45288

vendor priority summary link
alpine CVE-2023-45288: 3 source package rows (forgejo, go, rclone); 11 state rows across 5 repos (3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 11, open 0. https://security.alpinelinux.org/vuln/CVE-2023-45288
debian not yet assigned CVE-2023-45288 not yet assigned priority: Debian including 3 source packages (golang-1.15, golang-1.19, golang-golang-x-net), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 4, resolved 3. https://security-tracker.debian.org/tracker/CVE-2023-45288
gentoo normal CVE-2023-45288: 1 GLSA(s) (202408-07), 1 atom(s) (dev-lang/go); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-45288
redhat high https://access.redhat.com/security/cve/CVE-2023-45288
suse medium CVE-2023-45288 severity moderate: SUSE including 573 source package names (1.21-2.34.5:go1.21-1.21.9-150000.1.30.1, 1.21-2.34.5:go1.21-doc-1.21.9-150000.1.30.1, …), 1597 product×package rows across 375 product lines (Container bci/golang, Container suse/kubectl, … (375 product lines)): Fixed 1199, Known Affected 205, Known Not Affected 193. https://www.suse.com/security/cve/CVE-2023-45288/
ubuntu medium CVE-2023-45288 medium priority: Ubuntu including 14 source packages (golang, golang-1.10, …), 123 status rows across 11 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 79, needs-triage 29, released 7, not-affected 6, ignored 2. https://ubuntu.com/security/CVE-2023-45288

Affected software / configurations for CVE-2023-45288

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2023-45288

cvelogic Threat Intelligence