CVE-2026-73802: gitea-runner: workflow container.options passes host namespaces and capability flags to job container when privileged mode is disabled

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.5%, percentile 40: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 40% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes gitea.com/gitea/runner (Go) < 1.0.9-0.20260731160927-34bfa1915022, fixed in 1.0.9-0.20260731160927-34bfa1915022. Check your lockfile, including transitive dependencies.

What it is

Gitea Runner passes workflow-controlled container options into Docker job container configuration while privileged mode is disabled. Host namespace settings, expanded capabilities, and security profile overrides can remain effective despite Privileged being forced false. A workflow author able to run jobs on an affected Docker-backed runner can use these options to access host namespaces and execute commands as root on the runner host, bypassing the intended container isolation.

From the GitHub advisory

Summary actrunner appends workflow-controlled jobs. .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 actrunner:

- 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:

Attacker workflow YAML:

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

Weakness type: CWE-269.

Product: gitea.com/gitea/runner (Go) · Assigned by: Gitea · Published: 2026-10-14

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.47% probability of exploitation activity in the next 30 days; percentile 40.

Timeline

• 2026-10-02 — GitHub-reviewed advisory GHSA-x4q3-gcj3-m6cf published (critical)
• 2026-10-14 — CVE record published by Gitea
• 2026-10-18 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

1. GitHub Security Advisory GHSA-x4q3-gcj3-m6cf github.com
2. Gitea Runner 3.0.0 release announcement blog.gitea.com
3. gitea/runner v3.0.0 release gitea.com

Vulnerability records

1. GitHub Advisory GHSA-x4q3-gcj3-m6cf github.com
2. CVE.org record CVE-2026-73802 cve.org
3. NVD entry CVE-2026-73802 nvd.nist.gov

Other references from the CVE record and advisory

1. gitea.com gitea.com

Critical Go advisories · Today’s Security Digest