CVE-2026-12540: Redhat Satellite Command Injection RCE

CVE-2026-12540 Overview

CVE-2026-12540 is a command injection vulnerability in Foreman, the open source lifecycle management platform that also underpins Red Hat Satellite. The flaw resides in the foreman-rake errors:fetch_log task, which forwards the request_id parameter to an underlying shell command (typically grep) without adequate neutralization. An authenticated user with sudo rights to execute the rake task can inject shell metacharacters such as ;, ", or | to escape the intended command context and run arbitrary code. The weakness is tracked as CWE-78: Improper Neutralization of Special Elements used in an OS Command.

Critical Impact

Local attackers with sudo permission to the affected rake task can execute arbitrary commands, break scope boundaries, and compromise the confidentiality, integrity, and availability of the host.

Affected Products

• The Foreman project (theforeman:foreman)
• Red Hat Satellite (including Satellite 6.x)
• Red Hat Enterprise Linux 8 and 9 (as the Satellite distribution channel)

Discovery Timeline

• 2026-10-01 - CVE-2026-12540 published to the National Vulnerability Database
• 2026-10-07 - Advisory posted to the Openwall OSS-Security mailing list
• 2026-10-08 - Last updated in the NVD database

Technical Details for CVE-2026-12540

Vulnerability Analysis

Foreman exposes administrative maintenance tasks through the foreman-rake command runner. The errors:fetch_log task accepts a request_id argument so operators can filter log entries that correspond to a specific Foreman request. Internally, the task concatenates that argument into a shell invocation of grep against Foreman log files instead of passing it as an isolated execv-style argument. Because the input is not escaped and no safe argument-list execution model is used, shell metacharacters embedded in the request_id value are interpreted by the shell.

The scope changes from the rake task's bounded log-reading intent to full command execution under the invoking user's context. Since the task is typically run under sudo as the Foreman service account or root, the attacker gains high-impact code execution on the Satellite or Foreman server, including access to credentials, certificates, and managed-host communication channels.

Root Cause

The root cause is unsafe string interpolation of the request_id parameter into a shell command line in the errors:fetch_log rake task. Ruby's Kernel#system and backtick execution route through /bin/sh when a single string is supplied, allowing metacharacters to be reinterpreted rather than treated as literal data.

Attack Vector

Exploitation requires local access and sudo authorization to invoke the vulnerable rake task. The attacker supplies a crafted request_id value containing shell separators (;, |, &&) or command substitution (` , $()) to append arbitrary commands to the grep invocation. The payload executes with the privileges granted by the sudo rule, commonly root, and the scope change (S:C in the vulnerability metrics) reflects that the compromise crosses the rake task's limited security boundary.

No public proof-of-concept exploit code is referenced in the advisory data. Technical details are summarized in the Red Hat CVE Analysis for CVE-2026-12540 and the Openwall OSS-Security Post.

Detection Methods for CVE-2026-12540

Indicators of Compromise

• Entries in /var/log/secure or sudo logs showing invocation of foreman-rake errors:fetch_log with unusual request_id values containing ;, |, &, $(, or backticks.
• Unexpected child processes of ruby, rake, or foreman-rake such as sh -c, bash, curl, wget, nc, or python running shortly after the task is invoked.
• New or modified files under Foreman service directories, SSH authorized_keys additions for the foreman or root accounts, or outbound connections from the Satellite host to unknown destinations.

Detection Strategies

• Audit sudoers configuration for rules permitting foreman-rake errors:fetch_log and alert on any invocation of that task from non-approved operators.
• Deploy Linux auditd rules on execve calls where the parent is rake or foreman-rake and the child is a shell or network utility, which indicates command injection rather than normal log retrieval.
• Correlate rake task execution timestamps with process-tree and file-system telemetry collected by an EDR agent to flag deviations from the expected grep child process.

Monitoring Recommendations

• Forward /var/log/audit/audit.log, /var/log/secure, and Foreman production logs to a centralized SIEM for long-term retention and correlation.
• Create alerts on sudo use of foreman-rake outside documented maintenance windows and on any shell metacharacter patterns in rake arguments.
• Monitor outbound network connections from Satellite and Foreman hosts, since successful exploitation typically leads to tool-staging downloads or reverse shells.

How to Mitigate CVE-2026-12540

Immediate Actions Required

• Apply the Red Hat Satellite updates referenced in RHSA-2026:74503, RHSA-2026:74504, RHSA-2026:74505, and RHSA-2026:74506 to the Foreman package set.
• Review sudoers entries and remove any grant that allows non-administrative users to run foreman-rake errors:fetch_log until patches are deployed.
• Rotate credentials, API tokens, and certificates stored on Satellite or Foreman hosts if logs show suspicious invocations of the affected rake task.

Patch Information

Red Hat has issued security errata that address CVE-2026-12540 across supported Satellite streams running on Red Hat Enterprise Linux 8 and 9. Patch metadata and package lists are available in the Red Hat Security Advisory RHSA-2026:74503 and its companion errata, along with the Red Hat Bug Report #2489969. Upstream Foreman users should track the project's release notes and upgrade to the fixed version aligned with these errata.

Workarounds

• Restrict sudo permissions so that only trusted administrators can invoke foreman-rake, and remove targeted grants for the errors:fetch_log task.
• Enforce input hygiene at the operational layer by requiring that request_id arguments match a strict alphanumeric pattern before any operator is permitted to run the task.
• Place Satellite and Foreman management hosts behind jump servers with session recording, limiting local shell access to a small, auditable set of accounts.

# Example sudoers hardening — remove task-level grants until patched
# Before (vulnerable grant):
# operator ALL=(root) NOPASSWD: /usr/sbin/foreman-rake errors:fetch_log *
#
# After (restrict to admins only):
# %foreman-admins ALL=(root) /usr/sbin/foreman-rake
# Deny the specific task for everyone else:
# ALL ALL=(ALL) !/usr/sbin/foreman-rake errors\:fetch_log *