CVE-2021-3987Improper Access Control in janeczku/calibre-web
- 5.4MediumCVSS base score
- 0.35%Exploitation in 30 daysEPSS · top 71% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
An improper access control vulnerability exists in janeczku/calibre-web. The affected version allows users without public shelf permissions to create public shelves. The vulnerability is due to the `create_shelf` method in `shelf.py` not verifying if the user has the necessary permissions to create a public shelf. This issue can lead to unauthorized actions being performed by users.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
ID reserved
By @huntr_ai
- 3 years later
· 3 years later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| @huntr_aiCNA (assigner) | 3.0 | Medium5.4 | CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.35% · top 71% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.4.
Affected products
janeczku · janeczku/calibre-web
- affected unspecified – ≤ latest
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIcalibrewebGHSA-fj5v-w2jp-wqvj (opens in a new tab)
References
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2024-3244 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-fj5v-w2jp-wqvj (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-3987)Record last updated .