serverless-dns is a RethinkDNS resolver that deploys to Cloudflare Workers, Deno Deploy, Fastly, and Fly.io. Versions through abd including 0.1.30 have a vulnerability where the pr.yml GitHub Action interpolates in an unsafe manner untrusted input, specifically the github.event.pull_request.head.repo.clone_url and github.head_ref, to a command in the runner. Due to the action using the pull_request_target trigger it has permissive permissions by default. An unauthorized attacker can exploit this vulnerability to push arbitrary data to the repository. The subsequent impact on the end-user is executing the attackers' code when running serverless-dns. This is fixed in commit c5537dd, and expected to be released in 0.1.31.
https://github.com/serverless-dns/serverless-dns/security/advisories/GHSA-9g7x-737f-5xpc
https://github.com/serverless-dns/serverless-dns/commit/c5537dd7f203c59f2b86d1e295c2371f3533946a
Published: 2025-09-30
Updated: 2025-09-30
Base Score: 7.5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P
Severity: High
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: Critical
Base Score: 10
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Severity: Critical
EPSS: 0.00048