CVE-2020-27839

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.

Published: 2021-05-26 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-27839 is rated Moderate Risk (52.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.45%). EPSS rose +2.21% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-27839

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.24% 2.45% +2.21%
2 2026-05-27 0.34% 0.24% -0.10%
3 2026-03-04 — 0.34% —

Full EPSS history (36 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-27839

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2020-27839

OS Trackers for CVE-2020-27839

vendor priority summary link
alpine medium CVE-2020-27839: 1 source package rows (ceph); 5 state rows across 1 repos (edge-community); fixed 0, open 5. https://security.alpinelinux.org/vuln/CVE-2020-27839
debian not yet assigned CVE-2020-27839 not yet assigned priority: Debian including 1 source packages (ceph), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-27839
redhat medium — https://access.redhat.com/security/cve/CVE-2020-27839
suse medium CVE-2020-27839 severity moderate: SUSE including 389 source package names (0.38.1.5.8.40:librados2-15.2.9.83+g4275378de0-3.17.1, 0.38.1.5.8.40:librbd1-15.2.9.83+g4275378de0-3.17.1, …), 895 product×package rows across 67 product lines (Container caasp/v4/hyperkube, Container ses/6/cephcsi/cephcsi, … (67 product lines)): Fixed 552, Known Not Affected 334, Will Not Fix 9. https://www.suse.com/security/cve/CVE-2020-27839/
ubuntu medium CVE-2020-27839 medium priority: Ubuntu including 1 source packages (ceph), 9 status rows across 9 suites (bionic, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): released 6, not-affected 3. https://ubuntu.com/security/CVE-2020-27839

Affected software / configurations for CVE-2020-27839

Vendor Product Version Raw CPE
redhat ceph < 14.2.17 cpe:2.3:a:redhat:ceph:*:*:*:*:*:*:*:*
redhat ceph >= 15.2.0, < 15.2.9 cpe:2.3:a:redhat:ceph:*:*:*:*:*:*:*:*

References for CVE-2020-27839

URL Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1901330 Issue Tracking Vendor Advisory
cvelogic Threat Intelligence