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Fencer Vulns
medium 5.4

CVE-2020-27839 json

A flaw was found in ceph-dashboard.

published 2021-05-26 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-20337

cvss
5.4
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

A flaw was found in ceph-dashboard. The JSON Web Token (JWT) used for user authentication is stored by the frontend application in the browser’s localStorage which is potentially vulnerable to attackers via XSS attacks. The highest threat from this vulnerability is to data confidentiality and integrity.

Patch / fix

  • redhat ceph 14.2.17, 15.2.9
  • ceph Debian 14, Debian 13, Debian 12 14.2.18-1

debian advisories DEBIAN-CVE-2020-27839

  • ceph Ubuntu 20.04 LTS 15.2.12-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2020-27839

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 4 2:14.2.11-181.el7cp
  • ceph ceph storage 4 2:14.2.11-181.el8cp
  • librbd1 ceph storage 4 2:14.2.11-181.el7cp
  • librbd1 ceph storage 4 2:14.2.11-181.el8cp
  • librgw2 ceph storage 4 2:14.2.11-181.el7cp
  • librgw2 ceph storage 4 2:14.2.11-181.el8cp
  • rbd-nbd ceph storage 4 2:14.2.11-181.el7cp
  • rbd-nbd ceph storage 4 2:14.2.11-181.el8cp

red hat advisories RHSA-2021:2445

  • ceph SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 14.2.20.402+g6aa76c6815-3.60.1
  • deepsea Enterprise Storage 6 0.9.35+git.0.5a1dc9fe-3.34.1
  • ceph SLE Module for Basesystem 15 SP2, Enterprise Storage 7 15.2.9.83+g4275378de0-3.17.1

suse advisories SUSE-SU-2021:1473-1SUSE-SU-2021:1472-1SUSE-SU-2021:1108-1

  • ceph openSUSE Tumbleweed 16.2.6.463+g22e7612f9ad-1.1
  • ceph openSUSE Leap 15.2 15.2.9.83+g4275378de0-lp152.2.12.1
  • ceph-test openSUSE Leap 15.2 15.2.9.83+g4275378de0-lp152.2.12.1

opensuse advisories openSUSE-SU-2024:11652-1openSUSE-SU-2021:0544-1

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-2020-27839 updated cvss 5.4

ceph-dashboard: Don't use Browser's LocalStorage for storing JWT but Secure Cookies with proper HTTP Headers

  • Red Hat Ceph Storage 2 ceph, librbd1, librgw2, ceph-mds, ceph-mon, ceph-osd, +12 more Red Hat Openshift Container Storage 4 ceph Red Hat OpenStack Platform 13 (Queens) librbd1, librgw2, ceph-fuse, librados2, libcephfs2, python-rbd, +6 more
    affected: workaround, no fix planned “Do not store sensitive data in HTML5 localStorage, not even temporarily. Use cookies with appropriate security flags (secure, HttpOnly, SameSite).”
  • Red Hat Ceph Storage 4.2 MON ceph 14.2.11-181.el7cp, ceph 14.2.11-181.el8cp, librbd1 14.2.11-181.el7cp, librbd1 14.2.11-181.el8cp, librgw2 14.2.11-181.el7cp, librgw2 14.2.11-181.el8cp, +38 more Red Hat Ceph Storage 4.2 OSD ceph 14.2.11-181.el7cp, ceph 14.2.11-181.el8cp, librbd1 14.2.11-181.el7cp, librbd1 14.2.11-181.el8cp, librgw2 14.2.11-181.el7cp, librgw2 14.2.11-181.el8cp, +26 more Red Hat Ceph Storage 4.2 Tools ceph 14.2.11-181.el7cp, ceph 14.2.11-181.el8cp, librbd1 14.2.11-181.el7cp, librbd1 14.2.11-181.el8cp, librgw2 14.2.11-181.el7cp, librgw2 14.2.11-181.el8cp, +34 more
    fixed: vendor fix “Do not store sensitive data in HTML5 localStorage, not even temporarily. Use cookies with appropriate security flags (secure, HttpOnly, SameSite).” RHSA-2021:2445
  • Red Hat Ceph Storage 3 ceph, librbd1, librgw2, ceph-mds, ceph-mgr, ceph-mon, +15 more Red Hat Ceph Storage 4.2 MON python-waitress 1.4.2-1.el8ost, python3-waitress 1.4.2-1.el8ost Red Hat Ceph Storage 4.2 Tools libtcmu 1.5.2-4.el7cp, libtcmu 1.5.2-4.el8cp, ceph-iscsi 3.4-4.el7cp, ceph-iscsi 3.4-4.el8cp, tcmu-runner 1.5.2-4.el7cp, tcmu-runner 1.5.2-4.el8cp, +2 more 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

2.45% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N

Affected products

  • n/a ceph-dashboard

Classification

Weakness
  • CWE-522 Insufficiently Protected Credentials

References

Sources

Fencer Vulns 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.