CVE-2026-73802

CVE-2026-73802 is a critical-severity improper privilege management vulnerability in gitea.com/gitea/runner (go), affecting versions < 1.0.9-0.20260731160927-34bfa1915022. It is fixed in 1.0.9-0.20260731160927-34bfa1915022.

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Runtime intelligence, not another scanner.

Summary

gitea-runner: workflow container.options passes host namespaces and capability flags to job container when privileged mode is disabled

act_runner appends workflow-controlled jobs.<job>.container.options directly
to the Docker HostConfig for the job container. When runner privileged mode is
disabled, only Privileged is forced false. Host namespace flags, capability
expansion, and security profile overrides from workflow YAML are preserved in
the final HostConfig. A workflow author can enter host PID/IPC namespaces and
execute commands on the runner host as root.

Details

Source-to-sink path in act_runner:

  • ContainerSpec.Options accepts workflow YAML container.options
  • RunContext.options() appends workflow options to runner-level container options
  • Job container is created with Privileged: rc.Config.Privileged but also
    with Options: rc.options(ctx)
  • mergeContainerConfigs() parses Docker CLI-style options into HostConfig
  • When privileged mode is disabled, only copts.privileged is forced false
  • sanitizeConfig() only filters Binds and Mounts
  • Preserved dangerous HostConfig fields:
Privileged=false
PidMode=host
IpcMode=host
CapAdd=["ALL"]
SecurityOpt=["seccomp=unconfined","apparmor=unconfined"]

Attacker workflow YAML:

jobs:
  breakout:
    runs-on: ubuntu-latest
    container:
      image: ubuntu:22.04
      options: >-
        --pid=host --ipc=host --cap-add=ALL 
        --security-opt seccomp=unconfined 
        --security-opt apparmor=unconfined
    steps:
      - name: host namespace marker
        run: |
          nsenter -t 1 -m -u -i -n -p -- sh -c "id > /tmp/marker"

Fix Direction

Treat container.options as untrusted input. Reject or strip when
privileged mode is disabled:

  • Host namespaces: --pid=host, --ipc=host, --uts=host, --network=host
  • Capability expansion: --cap-add ALL, --cap-add SYS_ADMIN
  • Security overrides: --security-opt seccomp=unconfined, --security-opt apparmor=unconfined
  • Device access: --device, --device-cgroup-rule
  • Volume inheritance: --volumes-from
  • Runtime controls: --runtime, --cgroup-parent

Impact

An attacker who can submit a workflow to a repository using a shared
Docker-backed act_runner can:

  • Enter host PID, IPC, and mount namespaces
  • Execute arbitrary commands as root on the runner host
  • Access runner host secrets, deployment credentials, and environment variables
  • Pivot to adjacent jobs running on the same runner
  • Access internal build infrastructure reachable from the runner host

Critical severity for shared runners where untrusted users can trigger
workflows. High severity for single-tenant runners with privileged mode
explicitly disabled as a security control.

The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access. Typical impact: privilege escalation beyond the intended level.

CVE-2026-73802 has a CVSS score of 9.9 (Critical). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.9-0.20260731160927-34bfa1915022); upgrading removes the vulnerable code path.

Affected versions

gitea.com/gitea/runner (< 1.0.9-0.20260731160927-34bfa1915022)

Security releases

gitea.com/gitea/runner → 1.0.9-0.20260731160927-34bfa1915022 (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade gitea.com/gitea/runner to 1.0.9-0.20260731160927-34bfa1915022 or later to resolve this vulnerability.

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

  1. What is CVE-2026-73802? CVE-2026-73802 is a critical-severity improper privilege management vulnerability in gitea.com/gitea/runner (go), affecting versions < 1.0.9-0.20260731160927-34bfa1915022. It is fixed in 1.0.9-0.20260731160927-34bfa1915022. The application assigns, modifies, tracks, or checks privileges incorrectly, allowing a user to gain elevated access.
  2. How severe is CVE-2026-73802? CVE-2026-73802 has a CVSS score of 9.9 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which versions of gitea.com/gitea/runner are affected by CVE-2026-73802? gitea.com/gitea/runner (go) versions < 1.0.9-0.20260731160927-34bfa1915022 is affected.
  4. Is there a fix for CVE-2026-73802? Yes. CVE-2026-73802 is fixed in 1.0.9-0.20260731160927-34bfa1915022. Upgrade to this version or later.
  5. Is CVE-2026-73802 exploitable, and should I be worried? Whether CVE-2026-73802 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-73802 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-73802? Upgrade gitea.com/gitea/runner to 1.0.9-0.20260731160927-34bfa1915022 or later.

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