How severe is CVE-2021-25964?

CVE-2021-25964 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-25964 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-25964?

CVE-2021-25964 affects Janeczku Calibre-web. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-25964?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-25964 published?

CVE-2021-25964 was published on 2021-10-04 and last updated on 2026-06-17.

CVE-2021-25964

CVE-2021-25964 is a medium-severity vulnerability in Janeczku Calibre-web with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 1% (41st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Janeczku Calibre-web
Published: 2021-10-04
Last modified: 2026-06-17

Description

In “Calibre-web” application, v0.6.0 to v0.6.12, are vulnerable to Stored XSS in “Metadata”. An attacker that has access to edit the metadata information, can inject JavaScript payload in the description field. When a victim tries to open the file, XSS will be triggered.

Frequently asked questions

What is CVE-2021-25964?: In “Calibre-web” application, v0.6.0 to v0.6.12, are vulnerable to Stored XSS in “Metadata”. An attacker that has access to edit the metadata information, can inject JavaScript payload in the description field. When a victim tries to open the file, XSS will be triggered.
How severe is CVE-2021-25964?: CVE-2021-25964 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-25964 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-25964?: CVE-2021-25964 affects Janeczku Calibre-web. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-25964?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-25964 published?: CVE-2021-25964 was published on 2021-10-04 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:janeczku:calibre-web:*:*:*:*:*:*:*:*

More vulnerabilities in Janeczku Calibre-web

CVE-2022-0939 — Critical (CVSS 9.9): Server-Side Request Forgery (SSRF) in GitHub repository janeczku/calibre-web prior to 0.6.18.
CVE-2022-0767 — Critical (CVSS 9.9): Server-Side Request Forgery (SSRF) in GitHub repository janeczku/calibre-web prior to 0.6.17.
CVE-2025-7404 — Critical (CVSS 9.8): Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability in Calibre…
CVE-2023-2106 — Critical (CVSS 9.8): Weak Password Requirements in GitHub repository janeczku/calibre-web prior to 0.6.20.
CVE-2022-2525 — Critical (CVSS 9.8): Improper Restriction of Excessive Authentication Attempts in GitHub repository janeczku/calibre-web prior to 0.6.20.
CVE-2022-30765 — Critical (CVSS 9.8): Calibre-Web before 0.6.18 allows user table SQL Injection.

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