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Fencer Intel
medium 5.3

CVE-2021-3531 json

A flaw was found in the Red Hat Ceph Storage RGW in versions before 14.2.21.

published 5y ago modified 4mo ago also EUVD-2021-26847

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

A flaw was found in the Red Hat Ceph Storage RGW in versions before 14.2.21. When processing a GET Request for a swift URL that ends with two slashes it can cause the rgw to crash, resulting in a denial of service. The greatest threat to the system is of availability.

Patch / fix

  • redhat ceph 14.2.21
  • ceph Debian 14, Debian 13, Debian 12 14.2.21-1

debian advisories DEBIAN-CVE-2021-3531

  • ceph Ubuntu 18.04 LTS 12.2.13-0ubuntu0.18.04.10
  • ceph Ubuntu 20.04 LTS 15.2.12-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2021-3531

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • ceph ceph storage 5.1 2:16.2.7-98.el8cp
  • cephadm ceph storage 5.1 2:16.2.7-98.el8cp
  • librbd1 ceph storage 5.1 2:16.2.7-98.el8cp
  • librgw2 ceph storage 5.1 2:16.2.7-98.el8cp
  • rbd-nbd ceph storage 5.1 2:16.2.7-98.el8cp
  • ceph-mds ceph storage 5.1 2:16.2.7-98.el8cp
  • ceph-mgr ceph storage 5.1 2:16.2.7-98.el8cp
  • ceph-mon ceph storage 5.1 2:16.2.7-98.el8cp

red hat advisories RHSA-2022:1174

  • ceph SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 14.2.21.403+g69ab6ea274d-3.63.1
  • ceph SLE Module for Basesystem 15 SP3, SLE Module for Basesystem 15 SP2, SLE Micro 5.0 +1 more 15.2.12.83+g528da226523-3.25.1

suse advisories SUSE-SU-2021:1835-1SUSE-SU-2021:1834-1

  • ceph openSUSE Leap 15.3 15.2.12.83+g528da226523-3.25.1
  • ceph-test openSUSE Leap 15.3 15.2.12.83+g528da226523-3.25.1
  • ceph openSUSE Leap 15.2 15.2.12.83+g528da226523-lp152.2.18.1
  • ceph-test openSUSE Leap 15.2 15.2.12.83+g528da226523-lp152.2.18.1

opensuse advisories openSUSE-SU-2021:1834-1openSUSE-SU-2021:0833-1

  • ceph Alpine 3.16, Alpine 3.15, Alpine 3.14 16.2.4-r0
  • ceph16 Alpine 3.18, Alpine 3.17 16.2.4-r0

alpine advisories ALPINE-CVE-2021-3531

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Is CVE-2021-3531 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3531 updated cvss 5.3

ceph: RGW unauthenticated denial of service

  • Red Hat Ceph Storage 2 ceph, librbd1, librgw2, ceph-mds, ceph-mon, ceph-osd, +12 more Red Hat Ceph Storage 3 ceph, librbd1, librgw2, ceph-mds, ceph-mgr, ceph-mon, +15 more
    affected: no fix planned “Out of support scope”
  • Red Hat Ceph Storage 4 ceph, librbd1, librgw2, rbd-nbd, ceph-mds, ceph-mgr, +27 more
    affected: no fix available
  • Red Hat Enterprise Linux 7 librbd1, librados2, python-rbd, ceph-common, python-rados
    affected: no fix planned “Out of support scope”
  • Red Hat Openshift Container Storage 4 ceph Red Hat OpenStack Platform 13 (Queens) librbd1, librgw2, ceph-fuse, librados2, libcephfs2, python-rbd, +6 more
    affected: no fix planned “Will not fix”
  • Red Hat Ceph Storage 5.1 MON ceph 16.2.7-98.el8cp, cephadm 16.2.7-98.el8cp, librbd1 16.2.7-98.el8cp, librgw2 16.2.7-98.el8cp, ceph-mgr 16.2.7-98.el8cp, ceph-mon 16.2.7-98.el8cp, +22 more Red Hat Ceph Storage 5.1 OSD ceph 16.2.7-98.el8cp, librbd1 16.2.7-98.el8cp, librgw2 16.2.7-98.el8cp, ceph-osd 16.2.7-98.el8cp, ceph-base 16.2.7-98.el8cp, ceph-test 16.2.7-98.el8cp, +12 more Red Hat Ceph Storage 5.1 Tools ceph 16.2.7-98.el8cp, cephadm 16.2.7-98.el8cp, librbd1 16.2.7-98.el8cp, librgw2 16.2.7-98.el8cp, rbd-nbd 16.2.7-98.el8cp, ceph-mds 16.2.7-98.el8cp, +20 more
    fixed: vendor fix RHSA-2022:1174
  • Red Hat Ceph Storage 5.1 MON python-rsa 4.8-1.el8cp, python3-rsa 4.8-1.el8cp Red Hat Ceph Storage 5.1 Tools libtcmu 1.5.4-4.el8cp, ceph-iscsi 3.5-2.el8cp, tcmu-runner 1.5.4-4.el8cp, ceph-ansible 6.0.25.4-1.el8cp, cephadm-ansible 0.1-4.g6754c10.el8cp Red Hat Enterprise Linux 8 librbd1, librados2, libcephfs2, libradosstriper1 Red Hat Enterprise Linux 9 librbd1, librados2
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.18% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • n/a ceph

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.