{"schema":"threatline.record/2","record":{"id":"CVE-2026-73802","aliases":["GHSA-x4q3-gcj3-m6cf","GO-2026-6656"],"summary":"gitea-runner: workflow container.options passes host namespaces and capability flags to job container when privileged mode is disabled","details":"### Summary\nact_runner appends workflow-controlled `jobs.<job>.container.options` directly \nto the Docker HostConfig for the job container. When runner privileged mode is \ndisabled, only `Privileged` is forced false. Host namespace flags, capability \nexpansion, and security profile overrides from workflow YAML are preserved in \nthe final HostConfig. A workflow author can enter host PID/IPC namespaces and \nexecute commands on the runner host as root.\n\n### Details\nSource-to-sink path in act_runner:\n\n- `ContainerSpec.Options` accepts workflow YAML `container.options`\n- `RunContext.options()` appends workflow options to runner-level container options\n- Job container is created with `Privileged: rc.Config.Privileged` but also \n  with `Options: rc.options(ctx)`\n- `mergeContainerConfigs()` parses Docker CLI-style options into HostConfig\n- When privileged mode is disabled, only `copts.privileged` is forced false\n- `sanitizeConfig()` only filters `Binds` and `Mounts`\n- Preserved dangerous HostConfig fields:\n\n```text\nPrivileged=false\nPidMode=host\nIpcMode=host\nCapAdd=[\"ALL\"]\nSecurityOpt=[\"seccomp=unconfined\",\"apparmor=unconfined\"]\n```\n\nAttacker workflow YAML:\n```yaml\njobs:\n  breakout:\n    runs-on: ubuntu-latest\n    container:\n      image: ubuntu:22.04\n      options: >-\n        --pid=host --ipc=host --cap-add=ALL \n        --security-opt seccomp=unconfined \n        --security-opt apparmor=unconfined\n    steps:\n      - name: host namespace marker\n        run: |\n          nsenter -t 1 -m -u -i -n -p -- sh -c \"id > /tmp/marker\"\n```\n\n### Impact\nAn attacker who can submit a workflow to a repository using a shared \nDocker-backed act_runner can:\n\n- Enter host PID, IPC, and mount namespaces\n- Execute arbitrary commands as root on the runner host\n- Access runner host secrets, deployment credentials, and environment variables\n- Pivot to adjacent jobs running on the same runner\n- Access internal build infrastructure reachable from the runner host\n\nCritical severity for shared runners where untrusted users can trigger \nworkflows. High severity for single-tenant runners with privileged mode \nexplicitly disabled as a security control.\n\n### Fix Direction\nTreat `container.options` as untrusted input. Reject or strip when \nprivileged mode is disabled:\n\n- Host namespaces: `--pid=host`, `--ipc=host`, `--uts=host`, `--network=host`\n- Capability expansion: `--cap-add ALL`, `--cap-add SYS_ADMIN`\n- Security overrides: `--security-opt seccomp=unconfined`, `--security-opt apparmor=unconfined`\n- Device access: `--device`, `--device-cgroup-rule`\n- Volume inheritance: `--volumes-from`\n- Runtime controls: `--runtime`, `--cgroup-parent`","categories":["Libraries & packages"],"product":"gitea.com/gitea/runner","vendor":"Gitea","ecosystem":"go","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-x4q3-gcj3-m6cf","source_modified_at":"2026-10-02T23:18:13Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"go","name":"gitea.com/gitea/runner"},"range":"< 1.0.9-0.20260731160927-34bfa1915022"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-73802","source_modified_at":"2026-10-18T13:34:49.826Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Gitea Runner","vendor":"Gitea","versions":[{"lessThan":"3.0.0","status":"affected","version":"0","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-x4q3-gcj3-m6cf","source_modified_at":"2026-10-07T17:55:44.795358931Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"gitea.com/gitea/runner","ecosystem":"Go","purl":"pkg:golang/gitea.com/gitea/runner"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.0.9-0.20260731160927-34bfa1915022"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-x4q3-gcj3-m6cf","source_modified_at":"2026-10-02T23:18:13Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"go","name":"gitea.com/gitea/runner"},"version":"1.0.9-0.20260731160927-34bfa1915022"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-73802","source_modified_at":"2026-10-18T13:34:49.826Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Gitea Runner","ecosystem":null},"version":"3.0.0","basis":"first unaffected version stated in the CVE record"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-x4q3-gcj3-m6cf","source_modified_at":"2026-10-07T17:55:44.795358931Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"gitea.com/gitea/runner","ecosystem":"Go","purl":"pkg:golang/gitea.com/gitea/runner"},"version":"1.0.9-0.20260731160927-34bfa1915022"}],"cvss":9.9,"severity":"Critical","kev":{"listed":false},"epss":{"probability":0.00472,"percentile":0.39868,"score_date":"2026-10-23"},"published_at":"2026-10-14T14:37:55.141Z","modified_at":"2026-10-18T13:34:49.826Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-x4q3-gcj3-m6cf","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-02T23:18:13Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-73802","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-18T13:34:49.826Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-x4q3-gcj3-m6cf","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-07T17:55:44.795358931Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-73802","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/go-gitea/gitea/security/advisories/GHSA-x4q3-gcj3-m6cf","tags":["vendor-advisory"]},{"url":"https://gitea.com/gitea/runner/pulls/1058","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://gitea.com/gitea/runner/releases/tag/v3.0.0","tags":["release-notes"]},{"url":"https://github.com/advisories/GHSA-x4q3-gcj3-m6cf","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://blog.gitea.com/release-of-runner-3.0.0/","tags":["release-notes"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"total","assessed_at":"2026-10-18T13:34:45.738812Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-18T13:34:49.826Z","content_hash":"46d56df112ead41cf59f7613e5149668d1369a3fe3453edf70e2244ec2b72d3a"}}