CVE-2026-5484
CVE-2026-5484 — BookStackApp BookStack Chapter Export ExportFormatter.php chapterToMarkdown access control
A weakness has been identified in BookStackApp BookStack up to 26.03. Affected is the function chapterToMarkdown of the file app/Exports/ExportFormatter.php of the component Chapter Export Handler. Executing a manipulation of the argument pages can lead to improper access controls. It is possible to launch the attack remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 26.03.1 is able to address this issue. This patch is called 8a59895ba063040cc8dafd82e94024c406df3d04. It is advisable to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.
Published Updated Sources: cvelistV5, VulDB
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
chance of exploitation in 30 days
CVSS base
5.3
MEDIUM
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
PoC
none · proof-of-concept · active
Automatable
Yes
can an attacker script all four kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component
Affected scope
The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.
Vendors (1)
Products (1)
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 5.3 | CVSS 3.1 | MEDIUM | — | — | cvelistV5 |
Weakness & attack patterns
- CWE-284
- CWE-266
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
- T1027.009Obfuscated Files or Information: Embedded Payloads
- T1546.004Event Triggered Execution: .bash_profile and .bashrc
- T1546.016Event Triggered Execution: Installer Packages
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Search application, proxy, and WAF logs for requests touching /Exports/ExportFormatter.php.
References
8 on the record
- vuldb.com/vuln/355091
vdb-entry, technical-description
- vuldb.com/vuln/355091/cti
signature, permissions-required
- vuldb.com/submit/781762
third-party-advisory
- github.com/Ghufran2/CVE-Bookstack/blob/main/Permission%20Bypass%20in%20Markdown%20Chapter%20Export
exploit
- www.bookstackapp.com/blog/bookstack-release-v26-03-1/
related
- github.com/BookStackApp/BookStack/commit/8a59895ba063040cc8dafd82e94024c406df3d04
patch
- github.com/BookStackApp/BookStack/releases/tag/v26.03.1
patch
- github.com/BookStackApp/BookStack/
product
Elsewhere on this site
- bookstackappevery CVE for this vendor
- CWE-284other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.