High

amphp/http-client Denial of Service via HTTP/2 CONTINUATION Frames

  • Disclosed: 03.04.2024
  • Updated: 11.10.2026 10:22

Early versions of amphp/http-client with HTTP/2 support (v4.0.0-rc10 to 4.0.0) will collect HTTP/2 CONTINUATION frames in an unbounded buffer and will not check the header size limit until it has received the END_HEADERS flag, resulting in an OOM crash. Later versions of amphp/http-client (v4.1.0-rc1 and up) depend on amphp/http for HTTP/2 processing and will therefore need an updated version of amphp/http, see GHSA-qjfw-cvjf-f4fm.

Acknowledgements

Thank you to Bartek Nowotarski for reporting the vulnerability.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package amphp/http-client >= 4.0.0-rc10, < 4.1.0-rc1 4.1.0-rc1

References

CVSS score 8.2/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Weakness (CWE)
CWE-770, CWE-789
Platform
Composer
Package
amphp/http-client
Disclosed
03.04.2024
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-w8gf-g2vq-j2f4 - CC BY 4.0

Vulnerability history: amphp/http-client

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

Total entries
3
First → latest
04.2024 05.2024
Without a fix
1
Exploited in attacks
0

Severity breakdown

  • High 2
  • Medium 1

Disclosures per year

  1. 2024: 3
  2. 2025: 0
  3. 2026: 0
  1. Medium · 4.0 ghsa-8jp9-mpv9-98rj >= 4.0.0, < 4.4.0 4.4.0
  2. amphp/http-client Denial of Service via HTTP/2 CONTINUATION Frames this entry
    High · 8.2 ghsa-w8gf-g2vq-j2f4 >= 4.0.0-rc10, < 4.1.0-rc1 4.1.0-rc1
  3. High · 8.2 CVE-2024-2653 >= 4.0.0-rc10, <= 4.0.0 no fix

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