amphp/http-client Denial of Service via HTTP/2 CONTINUATION Frames
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- Denial of service
- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from GitHub. Impact type from CWE-770.
Summary
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](https://github.com/amphp/http/security/advisories/GHSA-qjfw-cvjf-f4fm). ## Acknowledgements Thank you to [Bartek Nowotarski](https://nowotarski.info/) for reporting the vulnerability.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | amphp/http-client (Packagist) | 4.0.0-rc10 to before 4.1.0-rc1 | 4.1.0-rc1 | Patch available | GHSA-w8gf-g2vq-j2f4 |
- amphp/http-client (Packagist) Vendor— Affected 4.0.0-rc10 to before 4.1.0-rc1 Fixed in 4.1.0-rc1 Patch available GHSA-w8gf-g2vq-j2f4
Remediation
- Fix · GHSA-w8gf-g2vq-j2f4 amphp/http-client (Packagist) Fixed in 4.1.0-rc1 Advisory →
Timeline
- 2026-10-03 Threatist record created from GHSA-w8gf-g2vq-j2f4
References
Sources
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