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Fencer Intel
medium 6.3

CVE-2026-27605 json

Chartbrew: Stored Cross-Site Scripting (XSS) via File Upload API

published 8mo ago modified 4mo ago also EUVD-2026-9980

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

Chartbrew is an open-source web application that can connect directly to databases and APIs and use the data to create charts. Prior to version 4.8.4, the application allows uploading files (project logos) without validating the file type or content. It trusts the extension provided by the user. These files are saved to the uploads/ directory and served statically. An attacker can upload an HTML file containing malicious JavaScript. Since authentication tokens are likely stored in localStorage (as they are returned in the API body), this XSS can lead to account takeover. This issue has been patched in version 4.8.4.

Patch / fix

  • depomo chartbrew 4.8.4

Is CVE-2026-27605 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/chartbrew/chartbrew/security/advisories/GHSA-jf6m-hm53-c364 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:N
NVD 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected products

  • chartbrew chartbrew

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel 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.