Apache HTTP Server: mod_proxy prior to 2.4.55 allows a backend to trigger HTTP response splitting
Published Jan 17, 2023 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Apache HTTP Server: mod_proxy prior to 2.4.55 allows a backend to trigger HTTP response splitting
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- LOW
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Jan 17, 2023 · Last refreshed Nov 3, 2026