RCE in Bookstackapp Bookstack

CVE-2020-5256

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.9 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L.

EPSS exploit prediction

EPSS: 0.020 (79.6th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 79.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2020-5256: held from 0.020 to 0.020.

EPSS over last 30 days · oldest: 0.020 · newest: 0.020 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2020-5256?
CVE-2020-5256 is a high-severity vulnerability in Bookstackapp Bookstack, classified under Eval Injection. CVSS score: 7.9/10. Published 2020-03-09.
How severe is CVE-2020-5256?
High severity. CVSS v3 base score is 7.9 out of 10.
Is CVE-2020-5256 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.