Insights-runtime-extractor: insights-runtime-extractor: container escape via privileged binary execution
Summary
| CVE | CVE-2026-104795 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-14 11:16:59 UTC |
| Updated | 2026-10-14 16:17:31 UTC |
| Description | The insights-runtime-extractor runs as a privileged DaemonSet (`hostPID: true`) that scans container processes for runtime fingerprinting. When scanning a container, the coordinator: 1. **fork()s** a child process 2. **setns()** into the target container's PID and mount namespaces 3. **fchdir()** back to an orphaned FD pointing at the extractor's own root filesystem (where `/crio.sock` is hostPath-mounted) 4. Calls **only `seteuid(target_uid)`** — changing the effective UID but leaving the **real UID and saved-set-UID at 0** and **retaining the permitted capability set** 5. The `check_no_privileged_perms()` guard inspects only the Effective capability set (so it passes), and is **skipped entirely when the target runs as uid 0** 6. The `VersionExecutable` fingerprint invokes `fpr_kind_executable` with `process.command_line[0]` — the target's argv[0], read from `/proc/<pid>/cmdline` and **fully controlled by the workload** 7. `fpr_kind_executable` calls `exec.Command(executable, "--version").Output()` — executing the **workload's own binary** inside the workload's mount namespace while **ruid=0 in the host user namespace** The executed process can call `setuid(0)` to restore full root with `CAP_SYS_ADMIN`, and inherits the orphaned cwd which resolves into the extractor container's filesystem containing the host CRI-O socket. ## Affected Code ### 1. Insufficient privilege drop (Rust — extractor coordinator) **File:** `extractor/src/insights_runtime_extractor.rs` ```rust // Lines 139-146 — seteuid-only drop, guard skipped for root containers join_process_namespaces(process.pid)?; change_dir(current_dir); switch_user(*process.uid)?; if *process.uid != 0 { perms::check_no_privileged_perms() .expect("Must not have privileged permissions to run fingerprints"); } fingerprint::run_fingerprints(&config, out_dir, &process); ``` ```rust // Lines 182-185 — only effective UID changed; ruid/suid stay 0 fn switch_user(uid: u32) -> Result<(), ScannerError> { debug!("... Becoming user: {uid}"); seteuid(uid.into()).map_err(|e| ScannerError::Errno(e)) } ``` ### 2. Execution of untrusted binary (Go — fingerprint) **File:** `fingerprints/pkg/utils/file.go` ```go // Lines 75-80 — executes a path taken verbatim from workload's argv[0] func GetExecutableVersionOutput(executable string) (string, error) { out, err := exec.Command(executable, "--version").Output() if err != nil { return "", err } return string(out), nil } ``` ### 3. Workload-controlled path forwarded (Rust — version_executable) **File:** `version_executable.rs` ```rust // Lines 29-34 — workload-controlled command_line[0] forwarded to fingerprint return Some(vec![ fpr_kind_executable, out_dir.to_string(), String::from(&process.command_line[0]), String::from(&version_executable.runtime_kind_name), ]); ``` ## Attack Pattern **Attacker:** Any tenant able to schedule a pod (unprivileged, any namespace) **Victim:** The node running the insights-runtime-extractor DaemonSet **Trigger:** Automatic — the DaemonSet scans all container processes on the node **Attack sequence:** 1. Attacker creates a pod whose process name matches a configured versioned-executable pattern (`node`, `python`, `python3`, `MainThread`, or contains `java`) 2. The pod's main binary (at the path matching argv[0]) is a malicious executable that calls `setuid(0)` to restore root 3. When the insights operator triggers a scan, the DaemonSet forks, enters the attacker's mount namespace, and executes the attacker's binary with ruid=0 4. The attacker's code regains full root with `CAP_SYS_ADMIN` in the host user namespace 5. The inherited cwd contains the host CRI-O socket → full node compromise |
Risk And Classification
Primary CVSS: v3.1 8.8 HIGH from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Problem Types: CWE-250 | CWE-250 Execution with Unnecessary Privileges
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 8.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
| 3.1 | CNA | CVSS | 8.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
ChangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/security/cve/CVE-2026-104795 | [email protected] | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-09-30T12:50:08.063Z | Reported to Red Hat. |
| CNA | 2026-10-14T09:47:53.272Z | Made public. |
Workarounds
CNA: The vulnerability requires a code fix to implement a complete privilege drop (setting all three UID/GID fields, clearing all Linux capability sets, and setting `PR_SET_NO_NEW_PRIVS`) before executing any fingerprint binary.
There are currently no legacy QID mappings associated with this CVE.