{"id":"CVE-2026-104795","published":"2026-10-14T11:16:59.937","lastModified":"2026-10-15T16:33:26.290","description":"The insights-runtime-extractor runs as a privileged DaemonSet (`hostPID: true`)\nthat scans container processes for runtime fingerprinting. When scanning a\ncontainer, the coordinator:\n\n1. **fork()s** a child process\n2. **setns()** into the target container's PID and mount namespaces\n3. **fchdir()** back to an orphaned FD pointing at the extractor's own root\n   filesystem (where `/crio.sock` is hostPath-mounted)\n4. Calls **only `seteuid(target_uid)`** — changing the effective UID but leaving\n   the **real UID and saved-set-UID at 0** and **retaining the permitted\n   capability set**\n5. The `check_no_privileged_perms()` guard inspects only the Effective capability\n   set (so it passes), and is **skipped entirely when the target runs as uid 0**\n6. The `VersionExecutable` fingerprint invokes `fpr_kind_executable` with\n   `process.command_line[0]` — the target's argv[0], read from\n   `/proc/<pid>/cmdline` and **fully controlled by the workload**\n7. `fpr_kind_executable` calls `exec.Command(executable, \"--version\").Output()`\n   — executing the **workload's own binary** inside the workload's mount\n   namespace while **ruid=0 in the host user namespace**\n\nThe executed process can call `setuid(0)` to restore full root with\n`CAP_SYS_ADMIN`, and inherits the orphaned cwd which resolves into the extractor\ncontainer's filesystem containing the host CRI-O socket.\n\n## Affected Code\n\n### 1. Insufficient privilege drop (Rust — extractor coordinator)\n\n**File:** `extractor/src/insights_runtime_extractor.rs`\n\n```rust\n// Lines 139-146 — seteuid-only drop, guard skipped for root containers\njoin_process_namespaces(process.pid)?;\nchange_dir(current_dir);\nswitch_user(*process.uid)?;\nif *process.uid != 0 {\n    perms::check_no_privileged_perms()\n        .expect(\"Must not have privileged permissions to run fingerprints\");\n}\nfingerprint::run_fingerprints(&config, out_dir, &process);\n```\n\n```rust\n// Lines 182-185 — only effective UID changed; ruid/suid stay 0\nfn switch_user(uid: u32) -> Result<(), ScannerError> {\n    debug!(\"... Becoming user: {uid}\");\n    seteuid(uid.into()).map_err(|e| ScannerError::Errno(e))\n}\n```\n\n### 2. Execution of untrusted binary (Go — fingerprint)\n\n**File:** `fingerprints/pkg/utils/file.go`\n\n```go\n// Lines 75-80 — executes a path taken verbatim from workload's argv[0]\nfunc GetExecutableVersionOutput(executable string) (string, error) {\n    out, err := exec.Command(executable, \"--version\").Output()\n    if err != nil {\n        return \"\", err\n    }\n    return string(out), nil\n}\n```\n\n### 3. Workload-controlled path forwarded (Rust — version_executable)\n\n**File:** `version_executable.rs`\n\n```rust\n// Lines 29-34 — workload-controlled command_line[0] forwarded to fingerprint\nreturn Some(vec![\n    fpr_kind_executable,\n    out_dir.to_string(),\n    String::from(&process.command_line[0]),\n    String::from(&version_executable.runtime_kind_name),\n]);\n```\n\n## Attack Pattern\n\n**Attacker:** Any tenant able to schedule a pod (unprivileged, any namespace)\n**Victim:** The node running the insights-runtime-extractor DaemonSet\n**Trigger:** Automatic — the DaemonSet scans all container processes on the node\n\n**Attack sequence:**\n\n1. Attacker creates a pod whose process name matches a configured\n   versioned-executable pattern (`node`, `python`, `python3`, `MainThread`,\n   or contains `java`)\n2. The pod's main binary (at the path matching argv[0]) is a malicious\n   executable that calls `setuid(0)` to restore root\n3. When the insights operator triggers a scan, the DaemonSet forks, enters the\n   attacker's mount namespace, and executes the attacker's binary with ruid=0\n4. The attacker's code regains full root with `CAP_SYS_ADMIN` in the host user\n   namespace\n5. The inherited cwd contains the host CRI-O socket → full node compromise","cvssScore":8.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cwes":["CWE-250"],"vendors":[],"products":[],"references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-104795","tags":[]},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2543917","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}