CVE-2021-3531Public exploitNetwork attack vector

Unauthenticated gateway crash via double-slash Swift path

Published May 18, 2021 · Updated Aug 3, 2024

Denial of service in Red Hat Ceph Storage RGW before 14.2.21 allows remote attackers to crash the gateway via a crafted Swift GET request. RGWSwiftWebsiteHandler::is_web_dir removes a trailing slash from subdir_name and passes the resulting empty value onward, reaching an assertion in RGWObjectCtx::set_atomic. No authentication is required; only the path before the bucket name must be valid, and the named bucket need not exist or be public.

CVSS severity5.3
Medium
EPSS probability2.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in Red Hat Ceph Storage RGW before 14.2.21 allows remote attackers to crash the gateway via a crafted Swift GET request. RGWSwiftWebsiteHandler::is_web_dir removes a trailing slash from subdir_name and passes the resulting empty value onward, reaching an assertion in RGWObjectCtx::set_atomic. No authentication is required; only the path before the bucket name must be valid, and the named bucket need not exist or be public.

The record

CVE
CVE-2021-3531
Published
May 18, 2021
Updated
Aug 3, 2024
Vendor
389 Directory Server
Product
Red Hat Ceph Storage
Classifications
CWE-617, CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=ceph 14.2.21

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat Ceph Storageversion=ceph 14.2.21

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-617Reachable Assertion
CWE-20Improper Input Validation
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo