CVE-2026-110101

Koillection through 1.8.4 contains a stored cross-site scripting vulnerability that allows authenticated users to upload HTML files as Datum file attachments lacking MIME restrictions. Attackers can upload HTML payloads via POST /api/data/{id}/file, served as text/html from public/uploads, executing JavaScript in victims' sessions to perform actions on their behalf.

CVSS 4.0

5.1CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

CVSS 3.1

5.4CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 18% of CVEs (scores of 2026-10-25)

CWE

CWE-79

Published

2026-10-13

Modified

2026-10-16

Record from

the NVD, synced 2026-10-19

References

• https://github.com/benjaminjonard/koillection/blob/1.8.4/src/Entity/Datum.php#L141-L145
• https://github.com/benjaminjonard/koillection/blob/1.8.4/src/Service/ImageHandler.php#L43-L50
• https://github.com/benjaminjonard/koillection/issues/1609
• https://github.com/benjaminjonard/koillection/releases/tag/1.8.4
• https://www.vulncheck.com/advisories/koillection-through-1.8.4-stored-xss-via-datum-file-attachment-uploads

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