CVE-2026-27824

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Source
https://cve.org/CVERecord?id=CVE-2026-27824
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27824.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-27824
Aliases
  • GHSA-vhxc-r7v8-2xrw
Downstream
Published
2026-02-27T19:46:07.612Z
Modified
2026-03-03T02:35:48.560171Z
Severity
  • 5.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N CVSS Calculator
Summary
calibre has IP Ban Bypass via X-Forwarded-For Header Spoofing
Details

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.

Database specific 
{
    "cwe_ids": [
        "CWE-307",
        "CWE-346"
    ],
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27824.json"
}
References

Affected packages

Git / github.com/kovidgoyal/calibre

Affected ranges

Type
GIT
Repo
https://github.com/kovidgoyal/calibre
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
0fe2747ab1959e715a239a7fe81eaa85692eb004
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "fixed": "9.4.0"
        }
    ]
}

Affected versions

0.*
0.9.33
0.9.34
0.9.35
0.9.36
0.9.37
v0.*
v0.9.38
v0.9.39
v0.9.40
v0.9.41
v0.9.42
v0.9.43
v0.9.44
v1.*
v1.0.0
v1.1.0
v1.10.0
v1.11.0
v1.12.0
v1.13.0
v1.14.0
v1.15.0
v1.16.0
v1.17.0
v1.18.0
v1.19.0
v1.2.0
v1.20.0
v1.21.0
v1.22.0
v1.23.0
v1.24.0
v1.25.0
v1.26.0
v1.27.0
v1.28.0
v1.29.0
v1.3.0
v1.30.0
v1.31.0
v1.32.0
v1.33.0
v1.34.0
v1.35.0
v1.36.0
v1.37.0
v1.38.0
v1.39.0
v1.4.0
v1.40.0
v1.41.0
v1.42.0
v1.43.0
v1.44.0
v1.45.0
v1.46.0
v1.47.0
v1.48.0
v1.5.0
v1.6.0
v1.7.0
v1.8.0
v1.9.0
v2.*
v2.0.0
v2.1.0
v2.10.0
v2.11.0
v2.12.0
v2.13.0
v2.14.0
v2.15.0
v2.16.0
v2.17.0
v2.18.0
v2.19.0
v2.2.0
v2.20.0
v2.21.0
v2.22.0
v2.23.0
v2.24.0
v2.25.0
v2.26.0
v2.27.0
v2.28.0
v2.29.0
v2.3.0
v2.30.0
v2.31.0
v2.32.0
v2.32.1
v2.33.0
v2.34.0
v2.35.0
v2.36.0
v2.37.0
v2.37.1
v2.38.0
v2.39.0
v2.4.0
v2.40.0
v2.41.0
v2.42.0
v2.43.0
v2.44.0
v2.44.1
v2.45.0
v2.46.0
v2.47.0
v2.48.0
v2.49.0
v2.5.0
v2.50.0
v2.50.1
v2.51.0
v2.52.0
v2.53.0
v2.54.0
v2.55.0
v2.56.0
v2.57.0
v2.57.1
v2.58.0
v2.59.0
v2.6.0
v2.60.0
v2.61.0
v2.62.0
v2.63.0
v2.64.0
v2.65.0
v2.65.1
v2.66.0
v2.67.0
v2.68.0
v2.69.0
v2.7.0
v2.70.0
v2.71.0
v2.72.0
v2.73.0
v2.74.0
v2.75.0
v2.75.1
v2.76.0
v2.77.0
v2.78.0
v2.79.0
v2.79.1
v2.8.0
v2.80.0
v2.81.0
v2.82.0
v2.83.0
v2.84.0
v2.85.0
v2.85.1
v2.9.0
v3.*
v3.0.0
v3.1.0
v3.1.1
v3.10.0
v3.11.0
v3.11.1
v3.12.0
v3.13.0
v3.14.0
v3.15.0
v3.16.0
v3.17.0
v3.18.0
v3.19.0
v3.2.0
v3.2.1
v3.20.0
v3.21.0
v3.22.0
v3.22.1
v3.23.0
v3.24.0
v3.24.1
v3.24.2
v3.25.0
v3.26.0
v3.26.1
v3.27.0
v3.27.1
v3.28.0
v3.29.0
v3.3.0
v3.30.0
v3.31.0
v3.32.0
v3.33.0
v3.33.1
v3.34.0
v3.35.0
v3.36.0
v3.37.0
v3.38.0
v3.38.1
v3.39.0
v3.39.1
v3.4.0
v3.40.0
v3.40.1
v3.41.0
v3.41.1
v3.41.2
v3.41.3
v3.42.0
v3.43.0
v3.44.0
v3.45.0
v3.45.1
v3.45.2
v3.46.0
v3.47.0
v3.48.0
v3.5.0
v3.6.0
v3.7.0
v3.8.0
v3.9.0
v4.*
v4.0.0
v4.1.0
v4.10.0
v4.10.1
v4.11.0
v4.11.1
v4.11.2
v4.12.0
v4.13.0
v4.14.0
v4.15.0
v4.16.0
v4.17.0
v4.18.0
v4.19.0
v4.2.0
v4.20.0
v4.21.0
v4.22.0
v4.23.0
v4.3.0
v4.4.0
v4.5.0
v4.6.0
v4.7.0
v4.8.0
v4.9.0
v4.9.1
v4.99.17
v5.*
v5.0.0
v5.0.1
v5.1.0
v5.10.0
v5.10.1
v5.11.0
v5.12.0
v5.13.0
v5.14.0
v5.15.0
v5.16.0
v5.16.1
v5.17.0
v5.18.0
v5.19.0
v5.2.0
v5.20.0
v5.21.0
v5.22.0
v5.22.1
v5.23.0
v5.24.0
v5.25.0
v5.26.0
v5.27.0
v5.28.0
v5.29.0
v5.3.0
v5.30.0
v5.31.0
v5.31.1
v5.32.0
v5.33.0
v5.33.1
v5.33.2
v5.34.0
v5.35.0
v5.36.0
v5.37.0
v5.38.0
v5.39.0
v5.39.1
v5.4.0
v5.4.1
v5.4.2
v5.40.0
v5.41.0
v5.42.0
v5.43.0
v5.44.0
v5.5.0
v5.6.0
v5.7.0
v5.7.1
v5.7.2
v5.8.0
v5.8.1
v5.9.0
v6.*
v6.0.0
v6.1.0
v6.10.0
v6.11.0
v6.12.0
v6.13.0
v6.14.0
v6.14.1
v6.15.0
v6.15.1
v6.16.0
v6.17.0
v6.18.0
v6.18.1
v6.19.0
v6.19.1
v6.2.0
v6.2.1
v6.20.0
v6.21.0
v6.22.0
v6.23.0
v6.24.0
v6.25.0
v6.26.0
v6.27.0
v6.28.0
v6.28.1
v6.29.0
v6.3.0
v6.4.0
v6.5.0
v6.6.0
v6.6.1
v6.7.0
v6.7.1
v6.8.0
v6.9.0
v7.*
v7.0.0
v7.1.0
v7.10.0
v7.11.0
v7.12.0
v7.13.0
v7.14.0
v7.15.0
v7.16.0
v7.17.0
v7.18.0
v7.19.0
v7.2.0
v7.20.0
v7.21.0
v7.22.0
v7.23.0
v7.24.0
v7.25.0
v7.26.0
v7.3.0
v7.4.0
v7.5.0
v7.5.1
v7.6.0
v7.7.0
v7.8.0
v7.9.0
v8.*
v8.0.0
v8.0.1
v8.1.0
v8.1.1
v8.10.0
v8.11.0
v8.11.1
v8.12.0
v8.13.0
v8.14.0
v8.15.0
v8.16.0
v8.16.1
v8.16.2
v8.2.0
v8.2.1
v8.2.100
v8.3.0
v8.4.0
v8.5.0
v8.6.0
v8.7.0
v8.8.0
v8.9.0
v9.*
v9.0.0
v9.1.0
v9.2.0
v9.2.1
v9.3.0
v9.3.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27824.json"