CVE-2026-112305: Semaphore UI through 2.19.16 RCE via Task Environment Ansible Variable Override

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-19 · updated 2026-10-19
Weakness: CWE-915

Description

Semaphore UI through 2.19.16 contains a remote code execution vulnerability that allows users with the task_runner role to override protected Ansible variables by supplying arbitrary keys in the task environment JSON. Attackers can POST tasks setting ansible_ssh_common_args with a ProxyCommand or ansible_connection=local to execute commands as the Semaphore server user, exposing encryption keys, SSH keys and stored secrets.

Affected products

semaphoreui Semaphore UI: through 2.19.16

References

https://github.com/semaphoreui/semaphore
https://github.com/semaphoreui/semaphore/blob/v2.19.16/api/projects/tasks.go#L39-L75
https://github.com/semaphoreui/semaphore/blob/v2.19.16/services/tasks/TaskRunner.go#L395-L431
https://github.com/semaphoreui/semaphore/pull/3888
https://www.vulncheck.com/advisories/semaphore-ui-through-2.19.16-rce-via-task-environment-ansible-variable-override

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