Vulnerability · Published Aug 19, 2025 · Assigned by GitHub_M

CVE-2025-55735flaskBlog Stored XSS Vulnerability

Medium 5.3

In plain English

A medium-severity cross-site scripting in FlaskBlog from DogukanUrker. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities).

Severity (CVSS 4.0)5.3Medium

Exploit odds (30 days)0.2%top 88.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
DogukanUrker	FlaskBlog	<= 2.8.0

Weakness: CWE-79, CWE-807 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References

https://github.com/DogukanUrker/FlaskBlog/security/advisories/GHSA-gj9v-qhc3-gcfx x_refsource_CONFIRM