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» GHSA-9c5c-5j4h-8q2c
Description
BookStack prior to version 21.11.3 is vulnerable to Improper Access Control. A logged-in user with no privileges OR guest user (if public access enabled) can access the /search/users/select AJAX endpoint meant for admins to manage audit logs, to dump all usernames existing in the Bookstack database. This can also be used to harvest email belonging to a user because BookStack also uses the code where(email, like, % . $search . %) to search for users based on email.
Basic information
Type
reviewed
Severity
medium Advisory on GitHub
Open advisory ↗ Repository advisory
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Source code
Browse source ↗ Published (advisory)
2021-12-16 19:40:26 UTC
Updated
2023-01-30 05:02:58 UTC
GitHub reviewed
2021-12-16 15:36:38 UTC
NVD published
2021-12-15
EPSS Score
Score
Percentile
0.43%
61.54%
CVSS Scores
Base score
Version
Severity
Vector
5.3
3.0
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CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
CWEs
CWE id
Name
CWE-284
Improper Access Control
Affected packages (1)
Vulnerable version ranges and first patched releases as published by GitHub.
Ecosystem
Package
Vulnerable range
First patched
Vulnerable functions
composer
ssddanbrown/bookstack < 21.11.3
21.11.3
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cvelogic
Threat Intelligence