Vulnerability in OpenStack Swift

CVE-2026-71190

In OpenStack Swift through 2.38.0, the proxy server Accept header parser contains a regular expression vulnerable to catastrophic backtracking (ReDoS). The "qdtext" pattern (?:[^"]|\\.)* allows an unauthenticated remote attacker to send a crafted Accept header that causes exponential CPU consumption in the proxy worker. A payload of 32 backslash-character pairs exceeds 30 seconds of CPU time. No authentication is required. Repeated requests can exhaust all proxy worker threads, resulting in a complete denial of service.

Vulnerability class: ReDoS (Regular Expression Denial of Service)

EPSS: 0.005 (44.2th percentile) — read the EPSS interpretation.