Calibre-Web Has a Stored Cross-Site Scripting (XSS) Vulnerability via the 'username' Field During User Creation

published 2025-12-02 11 mo ago modified 2026-11-04 4 d ago also GHSA-pc5g-j9j7-p4q3 , PYSEC-2026-1234 , EUVD-2025-200242

cvss: 3.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 12%
public exploits: 0; none known

A Stored Cross-Site Scripting (XSS) vulnerability in Calibre-Web v0.6.25 allows attackers to inject malicious JavaScript into the 'username' field during user creation. The payload is stored unsanitized and later executed when the /ajax/listusers endpoint is accessed.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-65858 updated 2026-06-28 cvss 3.5

Calibre-Web: Calibre: Calibre-Web: Stored Cross-Site Scripting (XSS) vulnerability in username field

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 11 mo ago (2025-12-02)

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 12% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/KhanhDuy155/calibre-web-CVE-2025-65858/blob/main/CVE-2025-65858.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
pypi	calibreweb	<=0.6.25	no fix listed

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /KhanhDuy155/calibre-web-CVE-2025-65858/blob/main/CVE-2025-65858.md
web, exploit, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2025-65858
advisory
github.com /janeczku/calibre-web
package
pypi.org /project/calibreweb
package
github.com /advisories/GHSA-pc5g-j9j7-p4q3
advisory

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.

Summary