Is CVE-2020-26211 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 1%.

What products does CVE-2020-26211 affect?

Tracked products affected include BookStack. Check the version you run to see whether it is affected.

How do I fix CVE-2020-26211?

Apply the vendor fix promptly. An official patch or advisory is available. Upgrade affected products to a fixed version.

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CVE-2020-26211

Q: What is CVE-2020-26211?

CVE-2020-26211 is a high-severity software vulnerability (Cross-site scripting (XSS)) with a CVSS score of 7.7. In BookStack before version 0.30.4, a user with permissions to edit a page could insert JavaScript code through the use of `javascript:` URIs within a link or form which would run, within the context of the current page, when clicked or sub

HIGH severity · CVSS 7.7 · Cross-site scripting (XSS)

7.7CVSS HIGH

Summary

In BookStack before version 0.30.4, a user with permissions to edit a page could insert JavaScript code through the use of `javascript:` URIs within a link or form which would run, within the context of the current page, when clicked or submitted. Additionally, a user with permissions to edit a page could insert a particular meta tag which could be used to silently redirect users to a alternative location upon visit of a page. Dangerous content may remain in the database but will be removed before being displayed on a page. If you think this could have been exploited the linked advisory provides a SQL query to test. As a workaround without upgrading, page edit permissions could be limited to only those that are trusted until you can upgrade although this will not address existing exploitation of this vulnerability. The issue is fixed in BookStack version 0.30.4.

Impact & exploitability

Attack vectorNetwork

Attack complexityHigh

Privileges requiredLow

User interactionRequired

Confidentiality impactHigh

Integrity impactHigh

Availability impactNone

Exploit probability (EPSS)1%

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

Affected products we track (1)

BookStack

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

Official patch: https://github.com/BookStackApp/BookStack/commit/bbd1384acbe7e52c21f89af69f2dc391c95dbf54 ↗

CVE-2020-26211

Summary

Impact & exploitability

Affected products we track (1)

Recommendation

Additional information