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CVE-2020-26211

26
FAUCET Score

CVE-2020-26211 is a cross-site scripting (XSS) vulnerability affecting BookStack versions prior to 0.30.4, allowing authenticated users with page editing permissions to inject malicious JavaScript via "javascript:" URIs or redirect users using a meta tag. This vulnerability carries a high CVSS score of 8.7 (AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N), indicating it can be exploited remotely with low complexity by a low-privileged user, leading to high confidentiality and integrity impacts. There is no evidence of active exploitation, publicly available exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.30.4CPE matchmatch criteria
cpe:2.3:a:bookstackapp:bookstack:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.7HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
1.3
Impact Score
5.8
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.08%
Probability of exploitation in next 30 days
EPSS Percentile
61.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0108 is in the 78th percentile among its peer group of 890 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

composerpatch availablevia ghsa
Product: ssddanbrown/bookstackFixed in: 0.30.4
github_advisorypatch availablevia nvd_reference
View patch

Vendor Advisories (1)

composerGHSA-ch37-ch8w-cfrqhigh

Bookstack Cross-site Scripting vulnerability

May 24, 2022

References

github.com / BookStackApp/BookStack/commit/bbd1384acbe7e52c21f89af69f2dc391c95dbf54
PatchThird Party Advisory
github.com / BookStackApp/BookStack/releases/tag/v0.30.4
Release NotesThird Party Advisory
github.com / BookStackApp/BookStack/security/advisories/GHSA-r2cf-8778-3jgp
Third Party Advisory
bookstackapp.com / blog/beta-release-v0-30-4
PatchVendor Advisory