{"id":"UBUNTU-CVE-2026-61628","details":"nginx ignition is a user interface for the nginx web server. Prior to version 2.41.1, `POST /api/users/onboarding/finish` is registered as anonymous (unauthenticated) and creates a user with full ReadWrite admin permissions. Because the handler uses a check-then-act (TOCTOU) pattern between the \"onboarding already completed?\" check and the user-creation write, with no atomic guard, a remote unauthenticated attacker who can reach an instance in its pre-onboarding state can create an administrator account for themselves — and concurrent requests can create multiple admin accounts in a single race. Version 2.41.1 patches the issue.","modified":"2026-09-22T22:56:30.223753626Z","published":"2026-09-22T00:00:00Z","upstream":["CVE-2026-61628"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-61628"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-61628"},{"type":"REPORT","url":"https://github.com/lucasdillmann/nginx-ignition/commit/0586b4e55ab780676d3553a2592979dfa2fb0183"},{"type":"REPORT","url":"https://github.com/lucasdillmann/nginx-ignition/security/advisories/GHSA-pxcx-fv34-x9p5"}],"affected":[{"package":{"name":"nginx","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/nginx?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.1-3ubuntu1","1.4.3-2ubuntu1","1.4.4-1ubuntu1","1.4.4-2ubuntu1","1.4.4-4ubuntu1","1.4.5-1ubuntu1","1.4.6-1ubuntu2","1.4.6-1ubuntu3","1.4.6-1ubuntu3.1","1.4.6-1ubuntu3.2","1.4.6-1ubuntu3.3","1.4.6-1ubuntu3.4","1.4.6-1ubuntu3.5","1.4.6-1ubuntu3.6","1.4.6-1ubuntu3.7","1.4.6-1ubuntu3.8","1.4.6-1ubuntu3.9","1.4.6-1ubuntu3.9+esm1","1.4.6-1ubuntu3.9+esm2","1.4.6-1ubuntu3.9+esm3","1.4.6-1ubuntu3.9+esm4","1.4.6-1ubuntu3.9+esm5","1.4.6-1ubuntu3.9+esm6","1.4.6-1ubuntu3.9+esm8"],"ecosystem_specific":{"binaries":[{"binary_name":"nginx","binary_version":"1.4.6-1ubuntu3.9+esm8"},{"binary_name":"nginx-common","binary_version":"1.4.6-1ubuntu3.9+esm8"},{"binary_name":"nginx-core","binary_version":"1.4.6-1ubuntu3.9+esm8"},{"binary_version":"1.4.6-1ubuntu3.9+esm8","binary_name":"nginx-extras"},{"binary_name":"nginx-full","binary_version":"1.4.6-1ubuntu3.9+esm8"},{"binary_name":"nginx-light","binary_version":"1.4.6-1ubuntu3.9+esm8"},{"binary_name":"nginx-naxsi","binary_version":"1.4.6-1ubuntu3.9+esm8"},{"binary_name":"nginx-naxsi-ui","binary_version":"1.4.6-1ubuntu3.9+esm8"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-61628.json"}},{"package":{"name":"nginx","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/nginx?arch=source&distro=esm-infra-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.9.3-1ubuntu1","1.9.6-2ubuntu1","1.9.6-2ubuntu2","1.9.9-0ubuntu1","1.9.9-1ubuntu1","1.9.10-0ubuntu1","1.9.10-1ubuntu1","1.9.11-0ubuntu1","1.9.11-0ubuntu2","1.9.12-0ubuntu1","1.9.13-0ubuntu1","1.9.14-0ubuntu1","1.9.15-0ubuntu1","1.10.0-0ubuntu0.16.04.1","1.10.0-0ubuntu0.16.04.2","1.10.0-0ubuntu0.16.04.3","1.10.0-0ubuntu0.16.04.4","1.10.3-0ubuntu0.16.04.1","1.10.3-0ubuntu0.16.04.2","1.10.3-0ubuntu0.16.04.3","1.10.3-0ubuntu0.16.04.4","1.10.3-0ubuntu0.16.04.5","1.10.3-0ubuntu0.16.04.5+esm1","1.10.3-0ubuntu0.16.04.5+esm2","1.10.3-0ubuntu0.16.04.5+esm3","1.10.3-0ubuntu0.16.04.5+esm4","1.10.3-0ubuntu0.16.04.5+esm5","1.10.3-0ubuntu0.16.04.5+esm6","1.10.3-0ubuntu0.16.04.5+esm7","1.10.3-0ubuntu0.16.04.5+esm9"],"ecosystem_specific":{"binaries":[{"binary_version":"1.10.3-0ubuntu0.16.04.5+esm9","binary_name":"nginx"},{"binary_version":"1.10.3-0ubuntu0.16.04.5+esm9","binary_name":"nginx-common"},{"binary_name":"nginx-core","binary_version":"1.10.3-0ubuntu0.16.04.5+esm9"},{"binary_name":"nginx-extras","binary_version":"1.10.3-0ubuntu0.16.04.5+esm9"},{"binary_name":"nginx-full","binary_version":"1.10.3-0ubuntu0.16.04.5+esm9"},{"binary_version":"1.10.3-0ubuntu0.16.04.5+esm9","binary_name":"nginx-light"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-61628.json"}},{"package":{"name":"nginx","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/nginx?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.12.1-0ubuntu2","1.13.6-2ubuntu1","1.13.6-2ubuntu2","1.13.10-1ubuntu1","1.13.12-0ubuntu1","1.14.0-0ubuntu1","1.14.0-0ubuntu1.1","1.14.0-0ubuntu1.2","1.14.0-0ubuntu1.3","1.14.0-0ubuntu1.4","1.14.0-0ubuntu1.5","1.14.0-0ubuntu1.6","1.14.0-0ubuntu1.7","1.14.0-0ubuntu1.9","1.14.0-0ubuntu1.10","1.14.0-0ubuntu1.11","1.14.0-0ubuntu1.11+esm1","1.14.0-0ubuntu1.11+esm2","1.14.0-0ubuntu1.11+esm4"],"ecosystem_specific":{"binaries":[{"binary_name":"libnginx-mod-http-auth-pam","binary_version":"1.14.0-0ubuntu1.11+esm4"},{"binary_version":"1.14.0-0ubuntu1.11+esm4","binary_name":"libnginx-mod-http-cache-purge"},{"binary_name":"libnginx-mod-http-dav-ext","binary_version":"1.14.0-0ubuntu1.11+esm4"},{"binary_name":"libnginx-mod-http-echo","binary_version":"1.14.0-0ubuntu1.11+esm4"},{"binary_version":"1.14.0-0ubuntu1.11+esm4","binary_name":"libnginx-mod-http-fancyindex"},{"binary_name":"libnginx-mod-http-geoip","binary_version":"1.14.0-0ubuntu1.11+esm4"},{"binary_name":"libnginx-mod-http-headers-more-filter","binary_version":"1.14.0-0ubuntu1.11+esm4"},{"binary_name":"libnginx-mod-http-image-filter","binary_version":"1.14.0-0ubuntu1.11+esm4"},{"binary_version":"1.14.0-0ubuntu1.11+esm4","binary_name":"libnginx-mod-http-lua"},{"binary_name":"libnginx-mod-http-ndk","binary_version":"1.14.0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