What is CVE-2021-4170?

CVE-2021-4170 is a medium-severity vulnerability in Janeczku Calibre-Web, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2022-01-16.

How severe is CVE-2021-4170?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Janeczku Calibre-Web

CVE-2021-4170

calibre-web is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Vulnerability class: XSS (Cross-Site Scripting)

Published 2022-01-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.2th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Janeczku Calibre-Web
Janeczku Janeczku/calibre-Web — versions unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

huntr.dev/bounties/ff395101-e392-401d-ab4f-579c63fbf6a0 (Exploit, Third Party Advisory)
github.com/janeczku/calibre-web/commit/7ad419dc8c12180e842a82118f4866ac3d074bc5 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-4170?: CVE-2021-4170 is a medium-severity vulnerability in Janeczku Calibre-Web, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2022-01-16.
How severe is CVE-2021-4170?: Medium severity. CVSS v3 base score is 5.4 out of 10.