SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

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.

HIGH 8.8EPSS 1.97%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.97%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
1.97% probability · 80th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-95, CWE-434
Affected
bookstackapp/bookstack
Source
security-advisories@github.com
EPSS trend
0%3%5%26 October 2026: 1.97%26 October 202626 October 2026

EPSS 2.0% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.