Skip to content
Fencer Intel
high 7.9

CVE-2020-5256 json

Remote Code Execution Through Image Uploads in BookStack

published 6y ago modified 4mo ago also GHSA-g9rq-x4fj-f5hx , EUVD-2020-0345

cvss
7.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

BookStack before version 0.25.5 has a vulnerability where a user could upload PHP files through image upload functions, which would allow them to execute code on the host system remotely. They would then have the permissions of the PHP process. This most impacts scenarios where non-trusted users are given permission to upload images in any area of the application. The issue was addressed in a series of patches in versions 0.25.3, 0.25.4 and 0.25.5. Users should upgrade to at least v0.25.5 to avoid this vulnerability.

Patch / fix

  • packagist ssddanbrown/bookstack 0.25.5
  • bookstackapp bookstack 0.25.3

Is CVE-2020-5256 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

1.97% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C
GitHub 3.1 7.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L

Affected packages

ecosystem package affected fixed in
packagist ssddanbrown/bookstack
<0.25.5
0.25.5

Affected products

  • BookStackApp BookStack

Classification

Weakness
  • CWE-95 Improper Neutralization of Directives in Dynamically Evaluated Code
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Intel 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.