Kavita: IDOR in /api/Download/*

published 2026-05-26 5 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-31937

cvss: 5.9; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 16%
public exploits: 0; none known

Kavita is a cross platform reading server. Prior to 0.9.0, the download, size-check, and chapter metadata endpoints do not enforce library-level authorization. A low-privileged user who knows or guesses a chapterId, volumeId, or seriesId belonging to a library they are not assigned to can download the full file contents, query file sizes, and read metadata for that content. This affects /api/Download/volume-size, /api/Download/chapter-size, /api/Download/series-size, /api/Download/volume, /api/Download/chapter, /api/Download/series, and /api/Chapter. This vulnerability is fixed in 0.9.0.

Patch / fix

fixed in 1

kavitareader kavita 0.9.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-05-26)

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/Kareadita/Kavita/security/advisories/GHSA-x3jq-95xw-gwvr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.9	CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CNA	4.0	5.9	CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Kareadita Kavita

Classification

Weakness

CWE-639 Authorization Bypass Through User-Controlled Key

References

github.com /Kareadita/Kavita/security/advisories/GHSA-x3jq-95xw-gwvr
exploit

Sources

CVE List CVE-2026-44776
NVD CVE-2026-44776

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary