CVE-2026-53925

Glances has arbitrary file write and command execution via `secure_popen` redirection and chaining operators in AMP command configuration

Published

2026-06-23

Modified

2026-07-21

EPSS percentile

8%

Aliases

GHSA-3vwc-qwhc-3mj7

Sources

github-advisory

Summary

### Summary The `secure_popen()` function in `glances/secure.py` interprets `>` (file redirection), `|` (pipe), and `&&` (command chaining) operators in command strings. These operators are applied without any validation on the target file path, piped command, or chained command. When Application Monitoring Process (AMP) modules load their `command` or `service_cmd` configuration values from `glances.conf`, those values are passed directly to `secure_popen()` with no sanitization. This allows an attacker who can modify the Glances configuration file to write arbitrary content to arbitrary filesystem paths (via `>`), chain arbitrary commands (via `&&`), or pipe command output to arbitrary programs (via `|`). Crucially, this vulnerability is **not mitigated** by the `--disable-config-exec` flag that was introduced to address CVE-2026-33641. That flag only disables backtick command execution in `config.get_value()`; it does not affect the `secure_popen()` function's interpretation of shell-like operators. ### Details **Affected code path 1 — Default AMP (`glances/amps/default/__init__.py:69`)** ```python res = self.get('command') # ... self.set_result(secure_popen(res).rstrip()) ``` The `command` config value is loaded from `[amp_ ]` sections via `GlancesAmp.load_config()` (`glances/amps/amp.py:81`): ```python self.configs[param] = config.get_value(amp_section, param).split(',') ``` **Affected code path 2 — SystemV AMP (`glances/amps/systemv/__init__.py:60`)** ```python res = secure_popen(self.get('service_cmd')) ``` The `service_cmd` config value is loaded from `[amp_systemv]` sections via the same `GlancesAmp.load_config()` method. **Sink — `secure_popen()` (`glances/secure.py:33-77`)** The function explicitly parses: - `>` for file redirection (line 39): `cmd.split('>')` — the path after `>` is used directly in `open(stdout_redirect, "w")` (line 71) with **no path validation**. - `|` for command piping (line 51): `cmd.split('|')` — each segment is executed as a separate `Popen` with stdout piped to the next. - `&&` for command chaining (line 27 in `secure_popen`): `cmd.split('&&')` — each segment is executed sequentially. None of these operators are sanitized or restricted when loading AMP configuration values. **Why `--disable-config-exec` does not help:** The `--disable-config-exec` flag (introduced for CVE-2026-33641) only prevents `system_exec()` from running backtick-embedded commands in `config.get_value()`. It does not affect how the resulting string value is processed by `secure_popen()`. A command value like `echo data > /etc/crontab` contains no backticks and passes through `get_value()` unchanged, then `secure_popen()` interprets the `>` operator and writes to the arbitrary path. ### PoC **Clean-checkout recipe:** 1. Create a test configuration file: ```bash cat > /tmp/poc-glances.conf /tmp/cve-poc-marker-amp [outputs] cors_origins=* EOF ``` 2. Run a Python script that simulates the AMP command execution path: ```python import sys sys.path.insert(0, '/path/to/glances') from glances.config import Config from glances.secure import secure_popen import os # Load config with --disable-config-exec ACTIVE (CVE-2026-33641 mitigation) config = Config(config_dir='/tmp/poc-glances.conf', disable_config_exec=True) # Read AMP command value (same as amp.py load_config) command = config.get_value('amp_poc', 'command') print(f'Command: {command!r}') # Execute (same as amps/default/__init__.py line 69) marker = '/tmp/cve-poc-marker-amp' assert not os.path.exists(marker), 'Clean state required' result = secure_popen(command) print(f'Result: {result!r}') # Verify arbitrary file write occurred assert os.path.exists(marker), 'VULNERABILITY NOT CONFIRMED' with open(marker) as f: content = f.read() print(f'Written to {marker}: {content!r}') assert 'POC_ARBITRARY_FILE_WRITE' in content # Cleanup os.remove(marker) p

Affected packages

Remediation: Upgrade to 4.5.5 or later.

References

• https://github.com/advisories/GHSA-3vwc-qwhc-3mj7