CVE-2025-53631Public exploitNetwork attack vector

Stored XSS via unsafe postContent rendering

Published Aug 14, 2025 · Updated Aug 14, 2025

Stored XSS in Dogukan Urker FlaskBlog 2.8.1 and earlier allows remote authenticated users to execute JavaScript in visitors' browsers. The /createpost handler trusts client-side sanitization, stores postContent without server-side neutralization, and two templates render it through Jinja's safe filter. A logged-in account able to create a post is required; viewing any page containing that post runs the stored script, exposing browser-accessible data or permitting page defacement.

CVSS severity5.3
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Dogukan Urker FlaskBlog 2.8.1 and earlier allows remote authenticated users to execute JavaScript in visitors' browsers. The /createpost handler trusts client-side sanitization, stores postContent without server-side neutralization, and two templates render it through Jinja's safe filter. A logged-in account able to create a post is required; viewing any page containing that post runs the stored script, exposing browser-accessible data or permitting page defacement.

The record

CVE
CVE-2025-53631
Published
Aug 14, 2025
Updated
Aug 14, 2025
Vendor
Dogukan Urker
Product
FlaskBlog
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 14, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 2.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Dogukan Urker · FlaskBlogversion=<= 2.8.1

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.3GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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