How severe is CVE-2021-3988?

CVE-2021-3988 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-3988 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-3988?

CVE-2021-3988 affects Janeczku Calibre-web. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-3988?

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

Does CVE-2021-3988 have an EU (EUVD) identifier?

Yes. CVE-2021-3988 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-3306.

When was CVE-2021-3988 published?

CVE-2021-3988 was published on 2024-11-15 and last updated on 2026-06-17.

CVE-2021-3988

CVE-2021-3988 is a medium-severity vulnerability in Janeczku Calibre-web with a CVSS 3.x base score of 6.1. 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 6.1)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2024-3306
Weakness: CWE-79
Affected product: Janeczku Calibre-web
Published: 2024-11-15
Last modified: 2026-06-17

Description

A Cross-site Scripting (XSS) vulnerability exists in janeczku/calibre-web, specifically in the file `edit_books.js`. The vulnerability occurs when editing book properties, such as uploading a cover or a format. The affected code directly inserts user input into the DOM without proper sanitization, allowing attackers to execute arbitrary JavaScript code. This can lead to various attacks, including stealing cookies. The issue is present in the code handling the `#btn-upload-cover` change event.

Frequently asked questions

What is CVE-2021-3988?: A Cross-site Scripting (XSS) vulnerability exists in janeczku/calibre-web, specifically in the file `edit_books.js`. The vulnerability occurs when editing book properties, such as uploading a cover or a format. The affected code directly inserts user input into the DOM without proper sanitization, allowing attackers to execute arbitrary JavaScript code. This can lead to various attacks, including stealing cookies. The issue is present in the code handling the `#btn-upload-cover` change event.
How severe is CVE-2021-3988?: CVE-2021-3988 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-3988 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-3988?: CVE-2021-3988 affects Janeczku Calibre-web. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-3988?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-3988 have an EU (EUVD) identifier?: Yes. CVE-2021-3988 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-3306.
When was CVE-2021-3988 published?: CVE-2021-3988 was published on 2024-11-15 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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