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Fencer Vulns
high 8.1

CVE-2024-4023 json

Stored XSS in flatpressblog/flatpress

published 2025-03-20 19 mo ago modified 2026-06-17 4 mo ago also EUVD-2024-32589

cvss
8.1
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

A stored cross-site scripting (XSS) vulnerability exists in flatpressblog/flatpress version 1.3. When a user uploads a file with a `.xsig` extension and directly accesses this file, the server responds with a Content-type of application/octet-stream, leading to the file being processed as an HTML file. This allows an attacker to execute arbitrary JavaScript code, which can be used to steal user cookies, perform HTTP requests, and access content of the same origin.

Patch / fix

  • flatpressblog flatpressblog/flatpress 1.3

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
19 mo ago

Exploit prediction

0.81% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • huntr.com https://huntr.com/bounties/ed803c13-0858-4c22-93ba-bf2384ab1e9d referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 8.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Affected products

  • flatpressblog flatpressblog/flatpress

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.