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Fencer Vulns
high 7.6

CVE-2021-3915 json

Unrestricted Upload of File with Dangerous Type in bookstackapp/bookstack

published 2021-11-13 4 y ago modified 2026-06-17 4 mo ago also GHSA-w2f4-hxpm-mq98 , EUVD-2021-2401

cvss
7.6
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

bookstack is vulnerable to Unrestricted Upload of File with Dangerous Type

Patch / fix

  • packagist ssddanbrown/bookstack 21.0.3
  • bookstackapp bookstackapp/bookstack 21.10.3

Exploit prediction

0.96% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.dev https://huntr.dev/bounties/fcb65f2d-257a-46f4-bac9-f6ded5649079 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 7.6 CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:H
NVD 3.1 5.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:P/I:N/A:N
GitHub 3.0 7.6 CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:H

Affected packages

ecosystem package affected fixed in
packagist ssddanbrown/bookstack
<21.0.3
21.0.3

Affected products

  • bookstackapp bookstackapp/bookstack

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.