CVE-2026-33868

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2026-33868
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33868.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-33868
Aliases
Published
2026-03-27T19:50:07.687Z
Modified
2026-04-10T05:42:56.985504Z
Severity
  • 4.3 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N CVSS Calculator
Summary
Mastodon has a GET-Based Open Redirect via '/web/%2F<domain>'
Details

Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.8, 4.4.15, and 4.3.21, an unauthenticated Open Redirect vulnerability (CWE-601) exists in the /web/* route due to improper handling of URL-encoded path segments. An attacker can craft a specially encoded URL that causes the application to redirect users to an arbitrary external domain, enabling phishing attacks and potential OAuth credential theft. The issue occurs because URL-encoded slashes (%2F) bypass Rails path normalization and are interpreted as host-relative redirects. Versions 4.5.8, 4.4.15, and 4.3.21 patch the issue.

Database specific 
{
    "cwe_ids": [
        "CWE-601"
    ],
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33868.json"
}
References

Affected packages

Git / github.com/mastodon/mastodon

Affected ranges

Type
GIT
Repo
https://github.com/mastodon/mastodon
Events
Introduced
26c78392f88afccebb8a88b68bc9994a9ce12648
Fixed
38e7bb9b866b5d207a511de093de25536f13e9c4
Database specific 
{
    "versions": [
        {
            "introduced": "4.5.0"
        },
        {
            "fixed": "4.5.8"
        }
    ]
}
Type
GIT
Repo
https://github.com/mastodon/mastodon
Events
Introduced
69e14246b838443985a541e97327494b8d2fdffb
Fixed
7c28ff90fcb7be07f8fec76f5cdbf4e094917f70
Database specific 
{
    "versions": [
        {
            "introduced": "4.4.0"
        },
        {
            "fixed": "4.4.15"
        }
    ]
}
Type
GIT
Repo
https://github.com/mastodon/mastodon
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
8fb494ba0adf87abeb2954cff214118324186edf
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "fixed": "4.3.21"
        }
    ]
}

Affected versions

v0.*
v0.1.0
v0.1.1
v0.1.2
v0.6
v0.7
v0.8
v0.9
v0.9.9
v1.*
v1.0
v1.1
v1.1.1
v1.1.2
v1.2
v1.2.1
v1.2.2
v1.3
v1.3.1
v1.3.2
v1.4.1
v1.4.2
v1.4.3
v1.4.4
v1.4.5
v1.4.6
v1.4.7
v1.4rc1
v1.4rc2
v1.4rc3
v1.4rc4
v1.4rc5
v1.4rc6
v1.5.0
v1.5.0rc1
v1.5.0rc2
v1.5.0rc3
v1.5.1
v1.6.0
v1.6.0rc1
v1.6.0rc2
v1.6.0rc3
v1.6.0rc4
v1.6.0rc5
v1.6.1
v2.*
v2.0.0
v2.0.0rc1
v2.0.0rc2
v2.0.0rc3
v2.0.0rc4
v2.1.0
v2.1.0rc1
v2.1.0rc2
v2.1.0rc3
v2.1.0rc4
v2.1.0rc5
v2.1.0rc6
v2.1.1
v2.1.2
v2.1.3
v2.2.0
v2.2.0rc1
v2.2.0rc2
v2.3.0
v2.3.0rc1
v2.3.0rc2
v2.3.0rc3
v2.3.1
v2.3.1rc1
v2.3.1rc2
v2.3.1rc3
v2.3.2
v2.3.2rc1
v2.3.2rc2
v2.3.2rc3
v2.3.2rc4
v2.3.2rc5
v2.4.0
v2.4.0rc1
v2.4.0rc2
v2.4.0rc3
v2.4.0rc4
v2.4.0rc5
v2.4.1
v2.4.1rc1
v2.4.1rc2
v2.4.1rc3
v2.4.1rc4
v2.4.2
v2.4.2rc1
v2.4.2rc2
v2.4.2rc3
v2.4.3
v2.4.3rc1
v2.4.3rc2
v2.4.3rc3
v2.5.0
v2.5.0rc1
v2.5.0rc2
v2.6.0
v2.6.0rc1
v2.6.0rc2
v2.6.0rc3
v2.6.0rc4
v2.6.1
v2.7.0
v2.7.0rc1
v2.7.0rc2
v2.7.0rc3
v2.7.1
v2.8.0
v2.8.0rc1
v2.8.0rc2
v2.8.0rc3
v2.8.1
v2.8.2
v2.9.0
v2.9.0rc1
v2.9.0rc2
v2.9.1
v2.9.2
v3.*
v3.0.0
v3.0.0rc1
v3.0.0rc2
v3.0.0rc3
v3.0.1
v3.1.0
v3.1.0rc1
v3.1.0rc2
v3.1.1
v3.1.2
v3.1.3
v3.1.4
v3.2.0
v3.2.0rc1
v3.2.0rc2
v3.3.0
v3.3.0rc1
v3.3.0rc2
v3.3.0rc3
v3.4.0
v3.4.0rc1
v3.4.0rc2
v3.4.1
v3.5.0
v3.5.0rc1
v3.5.0rc2
v3.5.0rc3
v3.5.1
v3.5.2
v3.5.3
v4.*
v4.0.0
v4.0.0rc1
v4.0.0rc2
v4.0.0rc3
v4.0.0rc4
v4.0.1
v4.0.2
v4.1.0
v4.1.0rc1
v4.1.0rc2
v4.1.0rc3
v4.2.0
v4.2.0-beta1
v4.2.0-beta2
v4.2.0-beta3
v4.2.0-rc1
v4.2.0-rc2
v4.3.0
v4.3.0-beta.1
v4.3.0-beta.2
v4.3.0-rc.1
v4.3.1
v4.3.10
v4.3.11
v4.3.12
v4.3.13
v4.3.14
v4.3.15
v4.3.16
v4.3.17
v4.3.18
v4.3.19
v4.3.2
v4.3.20
v4.3.3
v4.3.4
v4.3.5
v4.3.6
v4.3.7
v4.3.8
v4.3.9
v4.4.0
v4.4.1
v4.4.10
v4.4.11
v4.4.12
v4.4.13
v4.4.14
v4.4.2
v4.4.3
v4.4.4
v4.4.5
v4.4.6
v4.4.7
v4.4.8
v4.4.9
v4.5.0
v4.5.1
v4.5.2
v4.5.3
v4.5.4
v4.5.5
v4.5.6
v4.5.7

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-33868.json"