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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
OpenStack Swift unaffected
Version Status Constraints
1.9.1 affected < 2.35.4
2.36.0 affected < 2.36.3
2.37.0 affected < 2.37.3
2.38.0 affected —

No data.

No data.

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Vendors Products
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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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

Wed, 05 Aug 2026 07:15:00 +0000

Type Values Removed Values Added
Title OpenStack Swift Accept Header Regular Expression ReDoS Enables Denial of Service

Wed, 05 Aug 2026 05:30:00 +0000

Type Values Removed Values Added
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.
First Time appeared Openstack
Openstack swift
Weaknesses CWE-1333
CPEs cpe:2.3:a:openstack:swift:*:*:*:*:*:*:*:*
Vendors & Products Openstack
Openstack swift
References
Metrics cvssV4_0

{'score': 8.7, '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-08-05T04:54:03.020Z

Reserved: 2026-08-05T04:54:02.394Z

Link: CVE-2026-71190

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-05T07:00:10Z

Weaknesses