Home/CVE/A weakness has been identified in BookStackApp BookStack up to 26.03. Affected is the function chapterToMarkdown of the
CVE
CVE-2026-5484
A weakness has been identified in BookStackApp BookStack up to 26.03. Affected is the function chapterToMarkdown of the
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.
MEDIUM · CVSS 5.3
EPSS 0.00049
EPSS exploitation odds0.05% · top 84%
Monitor
- No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
No Sigma yet — build one →
YARA rules0
Look this up elsewhere - one-click external pivots
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How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-5484, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
EPSS exploitation probability
0.05%
Top 84%odds of exploitation in the next 30 days
CVSS metric silhouette
shape grows toward worst-case
CVSS vector breakdown
Exploitability - how they get in
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Impact - what breaks
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
VECTOR
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NLifecycle
- 03 Apr 2026Published to NVD
- 24 Apr 2026Last modified
Every entry is a recorded date - NVD publish/modify, CISA KEV add, public exploit disclosure. No inferred events.
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ATT&CK techniques
1Techniques this CVE enables - linked via CWE → CAPEC → ATT&CK. Pills with a solid outline are named directly in ATT&CK or Nuclei templates (high confidence); the others are linked through weakness mappings.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-19 · Embedding Scripts within Scripts CAPEC-CAPEC-441 · Malicious Logic Insertion CAPEC-CAPEC-478 · Modification of Windows Service Configuration CAPEC-CAPEC-479 · Malicious Root Certificate CAPEC-CAPEC-502 · Intent Spoof CAPEC-CAPEC-503 · WebView Exposure CAPEC-CAPEC-536 · Data Injected During Configuration CAPEC-CAPEC-546 · Incomplete Data Deletion in a Multi-Tenant Environment CAPEC-CAPEC-550 · Install New Service CAPEC-CAPEC-551 · Modify Existing Service CAPEC-CAPEC-552 · Install Rootkit CAPEC-CAPEC-556 · Replace File Extension Handlers
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Weakness Classification
CWE-284Improper Access Control
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Related CVEs
8CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.
CVE-2012-4549
A flaw was found in JBoss Enterprise Application Platform. The `processInvocatio...
same CWE-266
MEDIUM
CVE-2016-7070
A privilege escalation flaw was found in the Ansible Tower. When Tower before 3....
same CWE-266
HIGH
CVE-2016-7066
It was found that the improper default permissions on /tmp/auth directory in JBo...
same CWE-266
HIGH
CVE-2017-12711
An Incorrect Privilege Assignment issue was discovered in Advantech WebAccess ve...
same CWE-266
HIGH
CVE-2001-0781
Buffer overflow in SpoonFTP 1.0.0.12 allows remote attackers to execute arbitrar...
same CWE-284
CVE-2008-2947
Cross-domain vulnerability in Microsoft Internet Explorer 5.01 SP4, 6, and 7 all...
same CWE-284
CVE-2009-2092
IBM WebSphere Application Server (WAS) 7.0 before 7.0.0.5 does not properly read...
same CWE-284
CVE-2009-2631
Multiple clientless SSL VPN products that run in web browsers, including Stoneso...
same CWE-284
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References & Sources
8Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.