CVE-2025-55735

flaskBlog is a blog app built with Flask. In 2.8.0 and earlier, when creating a post, there's no validation of the content of the post stored in the variable "postContent". The vulnerability arises when displaying the content of the post using the | safe filter, that tells the engine to not escape the rendered content. This can lead to a stored XSS inside the content of the post. The code that causes the problem is in template/routes.html.

CVSS v4.0

5.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1

5.4 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS

0.21% chance of exploitation in the next 30 days, 11th percentile

Published

2025-08-19

Proof-of-concept exploits (1)

• DogukanUrker/FlaskBlog/security/advisories/GHSA-gj9v-qhc3-gcfx

References

• CVE Record
• NVD entry

Related

• CVE-2024-22414
• CVE-2025-28101
• CVE-2025-28102
• CVE-2025-28104
• CVE-2025-55734
• CVE-2025-55736