{"url":"http://public2.vulnerablecode.io/api/vulnerabilities/97049?format=json","vulnerability_id":"VCID-nj3z-4ya4-bqf7","summary":"calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.4.0, the calibre Content Server's brute-force protection mechanism uses a ban key derived from both `remote_addr` and the `X-Forwarded-For` header. Since the `X-Forwarded-For` header is read directly from the HTTP request without any validation or trusted-proxy configuration, an attacker can bypass IP-based bans by simply changing or adding this header, rendering the brute-force protection completely ineffective. This is particularly dangerous for calibre servers exposed to the internet, where brute-force protection is the primary defense against credential stuffing and password guessing attacks. Version 9.4.0 contains a fix for the issue.","aliases":[{"alias":"CVE-2026-27824"}],"fixed_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/1089403?format=json","purl":"pkg:deb/debian/calibre@6.13.0%2Brepack-2%2Bdeb12u6","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@6.13.0%252Brepack-2%252Bdeb12u6"},{"url":"http://public2.vulnerablecode.io/api/packages/1089404?format=json","purl":"pkg:deb/debian/calibre@8.5.0%2Bds-1%2Bdeb13u2","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@8.5.0%252Bds-1%252Bdeb13u2"},{"url":"http://public2.vulnerablecode.io/api/packages/582437?format=json","purl":"pkg:deb/debian/calibre@8.16.2%2Bds%2B~0.10.5-3~bpo13%2B1","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@8.16.2%252Bds%252B~0.10.5-3~bpo13%252B1"},{"url":"http://public2.vulnerablecode.io/api/packages/921612?format=json","purl":"pkg:deb/debian/calibre@9.4.0%2Bds%2B~0.10.5-1?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.4.0%252Bds%252B~0.10.5-1%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/582195?format=json","purl":"pkg:deb/debian/calibre@9.6.0%2Bds%2B~0.10.5-5?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.6.0%252Bds%252B~0.10.5-5%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/1041946?format=json","purl":"pkg:deb/debian/calibre@9.6.0%2Bds%2B~0.10.5-6?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.6.0%252Bds%252B~0.10.5-6%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/1062443?format=json","purl":"pkg:deb/debian/calibre@9.7.0%2Bds%2B~0.10.5-2?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.7.0%252Bds%252B~0.10.5-2%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/1102898?format=json","purl":"pkg:deb/debian/calibre@9.8.0%2Bds%2B~0.10.5-1?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.8.0%252Bds%252B~0.10.5-1%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/1112497?format=json","purl":"pkg:deb/debian/calibre@9.8.0%2Bds%2B~0.10.5-5?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.8.0%252Bds%252B~0.10.5-5%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/1113658?format=json","purl":"pkg:deb/debian/calibre@9.8.0%2Bds%2B~0.10.6-1?distro=trixie","is_vulnerable":false,"affected_by_vulnerabilities":[],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@9.8.0%252Bds%252B~0.10.6-1%3Fdistro=trixie"}],"affected_packages":[{"url":"http://public2.vulnerablecode.io/api/packages/582189?format=json","purl":"pkg:deb/debian/calibre@5.12.0%2Bdfsg-1%2Bdeb11u2?distro=trixie","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2w1b-b6qm-4qhf"},{"vulnerability":"VCID-b3vv-xdp2-7ub8"},{"vulnerability":"VCID-bjj5-ynf7-v7aa"},{"vulnerability":"VCID-dywq-dzuv-wka2"},{"vulnerability":"VCID-hgmk-8s7s-tfdb"},{"vulnerability":"VCID-jwpx-aqjh-dqej"},{"vulnerability":"VCID-mqmp-g7uy-gbg4"},{"vulnerability":"VCID-nj3z-4ya4-bqf7"},{"vulnerability":"VCID-vq4p-dvg4-eudz"},{"vulnerability":"VCID-x63d-4kux-cqcu"},{"vulnerability":"VCID-zhz3-1799-a7hk"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@5.12.0%252Bdfsg-1%252Bdeb11u2%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/582434?format=json","purl":"pkg:deb/debian/calibre@5.12.0%2Bdfsg-1%2Bdeb11u2","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2w1b-b6qm-4qhf"},{"vulnerability":"VCID-4gvv-bsf9-vqca"},{"vulnerability":"VCID-b3vv-xdp2-7ub8"},{"vulnerability":"VCID-bjj5-ynf7-v7aa"},{"vulnerability":"VCID-dywq-dzuv-wka2"},{"vulnerability":"VCID-favj-1bjh-9uff"},{"vulnerability":"VCID-hgmk-8s7s-tfdb"},{"vulnerability":"VCID-jwpx-aqjh-dqej"},{"vulnerability":"VCID-mqmp-g7uy-gbg4"},{"vulnerability":"VCID-nj3z-4ya4-bqf7"},{"vulnerability":"VCID-vq4p-dvg4-eudz"},{"vulnerability":"VCID-x63d-4kux-cqcu"},{"vulnerability":"VCID-zhz3-1799-a7hk"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@5.12.0%252Bdfsg-1%252Bdeb11u2"},{"url":"http://public2.vulnerablecode.io/api/packages/582191?format=json","purl":"pkg:deb/debian/calibre@6.13.0%2Brepack-2%2Bdeb12u5?distro=trixie","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2w1b-b6qm-4qhf"},{"vulnerability":"VCID-bjj5-ynf7-v7aa"},{"vulnerability":"VCID-dywq-dzuv-wka2"},{"vulnerability":"VCID-hgmk-8s7s-tfdb"},{"vulnerability":"VCID-jwpx-aqjh-dqej"},{"vulnerability":"VCID-mqmp-g7uy-gbg4"},{"vulnerability":"VCID-nj3z-4ya4-bqf7"},{"vulnerability":"VCID-vq4p-dvg4-eudz"},{"vulnerability":"VCID-x63d-4kux-cqcu"},{"vulnerability":"VCID-zhz3-1799-a7hk"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@6.13.0%252Brepack-2%252Bdeb12u5%3Fdistro=trixie"},{"url":"http://public2.vulnerablecode.io/api/packages/582435?format=json","purl":"pkg:deb/debian/calibre@6.13.0%2Brepack-2%2Bdeb12u5","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2w1b-b6qm-4qhf"},{"vulnerability":"VCID-bjj5-ynf7-v7aa"},{"vulnerability":"VCID-dywq-dzuv-wka2"},{"vulnerability":"VCID-hgmk-8s7s-tfdb"},{"vulnerability":"VCID-jwpx-aqjh-dqej"},{"vulnerability":"VCID-mqmp-g7uy-gbg4"},{"vulnerability":"VCID-nj3z-4ya4-bqf7"},{"vulnerability":"VCID-vq4p-dvg4-eudz"},{"vulnerability":"VCID-x63d-4kux-cqcu"},{"vulnerability":"VCID-zhz3-1799-a7hk"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@6.13.0%252Brepack-2%252Bdeb12u5"},{"url":"http://public2.vulnerablecode.io/api/packages/582436?format=json","purl":"pkg:deb/debian/calibre@8.5.0%2Bds-1%2Bdeb13u1","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2w1b-b6qm-4qhf"},{"vulnerability":"VCID-bjj5-ynf7-v7aa"},{"vulnerability":"VCID-dywq-dzuv-wka2"},{"vulnerability":"VCID-hgmk-8s7s-tfdb"},{"vulnerability":"VCID-jwpx-aqjh-dqej"},{"vulnerability":"VCID-mqmp-g7uy-gbg4"},{"vulnerability":"VCID-nj3z-4ya4-bqf7"},{"vulnerability":"VCID-vq4p-dvg4-eudz"},{"vulnerability":"VCID-x63d-4kux-cqcu"},{"vulnerability":"VCID-zhz3-1799-a7hk"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@8.5.0%252Bds-1%252Bdeb13u1"},{"url":"http://public2.vulnerablecode.io/api/packages/582193?format=json","purl":"pkg:deb/debian/calibre@8.5.0%2Bds-1%2Bdeb13u1?distro=trixie","is_vulnerable":true,"affected_by_vulnerabilities":[{"vulnerability":"VCID-2w1b-b6qm-4qhf"},{"vulnerability":"VCID-bjj5-ynf7-v7aa"},{"vulnerability":"VCID-dywq-dzuv-wka2"},{"vulnerability":"VCID-hgmk-8s7s-tfdb"},{"vulnerability":"VCID-jwpx-aqjh-dqej"},{"vulnerability":"VCID-mqmp-g7uy-gbg4"},{"vulnerability":"VCID-nj3z-4ya4-bqf7"},{"vulnerability":"VCID-vq4p-dvg4-eudz"},{"vulnerability":"VCID-x63d-4kux-cqcu"},{"vulnerability":"VCID-zhz3-1799-a7hk"}],"resource_url":"http://public2.vulnerablecode.io/packages/pkg:deb/debian/calibre@8.5.0%252Bds-1%252Bdeb13u1%3Fdistro=trixie"}],"references":[{"reference_url":"https://api.first.org/data/v1/epss?cve=CVE-2026-27824","reference_id":"","reference_type":"","scores":[{"value":"0.0002","scoring_system":"epss","scoring_elements":"0.0544","published_at":"2026-04-08T12:55:00Z"},{"value":"0.0002","scoring_system":"epss","scoring_elements":"0.05368","published_at":"2026-04-02T12:55:00Z"},{"value":"0.0002","scoring_system":"epss","scoring_elements":"0.05461","published_at":"2026-04-09T12:55:00Z"},{"value":"0.0002","scoring_system":"epss","scoring_elements":"0.05398","published_at":"2026-04-04T12:55:00Z"},{"value":"0.0002","scoring_system":"epss","scoring_elements":"0.05405","published_at":"2026-04-07T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07605","published_at":"2026-04-18T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07692","published_at":"2026-04-13T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07617","published_at":"2026-04-16T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07756","published_at":"2026-04-21T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.077","published_at":"2026-04-24T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07679","published_at":"2026-04-26T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07646","published_at":"2026-04-29T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07626","published_at":"2026-05-05T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07722","published_at":"2026-04-11T12:55:00Z"},{"value":"0.00027","scoring_system":"epss","scoring_elements":"0.07707","published_at":"2026-04-12T12:55:00Z"},{"value":"0.00029","scoring_system":"epss","scoring_elements":"0.08232","published_at":"2026-05-12T12:55:00Z"},{"value":"0.00029","scoring_system":"epss","scoring_elements":"0.08221","published_at":"2026-05-09T12:55:00Z"},{"value":"0.00029","scoring_system":"epss","scoring_elements":"0.08204","published_at":"2026-05-11T12:55:00Z"},{"value":"0.00029","scoring_system":"epss","scoring_elements":"0.08286","published_at":"2026-05-14T12:55:00Z"},{"value":"0.00029","scoring_system":"epss","scoring_elements":"0.08156","published_at":"2026-05-07T12:55:00Z"}],"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-27824"},{"reference_url":"https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-27824","reference_id":"","reference_type":"","scores":[],"url":"https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-27824"},{"reference_url":"https://github.com/kovidgoyal/calibre/security/advisories/GHSA-vhxc-r7v8-2xrw","reference_id":"GHSA-vhxc-r7v8-2xrw","reference_type":"","scores":[{"value":"5.3","scoring_system":"cvssv3.1","scoring_elements":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"},{"value":"Track","scoring_system":"ssvc","scoring_elements":"SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2026-03-02T12:54:19Z/"}],"url":"https://github.com/kovidgoyal/calibre/security/advisories/GHSA-vhxc-r7v8-2xrw"}],"weaknesses":[{"cwe_id":307,"name":"Improper Restriction of Excessive Authentication Attempts","description":"The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame, making it more susceptible to brute force attacks."},{"cwe_id":346,"name":"Origin Validation Error","description":"The product does not properly verify that the source of data or communication is valid."}],"exploits":[],"severity_range_score":"5.3 - 5.3","exploitability":"0.5","weighted_severity":"4.8","risk_score":2.4,"resource_url":"http://public2.vulnerablecode.io/vulnerabilities/VCID-nj3z-4ya4-bqf7"}