CVE-2022-47016 in tmux
Summary
by MITRE • 01/20/2023
A null pointer dereference issue was discovered in function window_pane_set_event in window.c in tmux 3.0 thru 3.3 allows attackers to cause denial of service or other unspecified impacts.
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Analysis
by VulDB Data Team • 01/21/2023
The vulnerability identified as CVE-2022-47016 represents a critical null pointer dereference flaw within the tmux terminal multiplexer software ecosystem. This issue resides in the window_pane_set_event function located in the window.c source file, affecting tmux versions 3.0 through 3.3 inclusive. The vulnerability stems from inadequate input validation and error handling mechanisms that fail to properly check for null pointer conditions before attempting memory access operations. When an attacker manipulates specific input parameters or triggers particular sequences within the tmux session management framework, the software attempts to dereference a null pointer, leading to immediate program termination and system instability.
The technical exploitation of this vulnerability occurs through the manipulation of window pane event handling mechanisms within tmux's core architecture. The window_pane_set_event function processes various event notifications related to terminal window operations, and when it encounters malformed or unexpected input data, the absence of proper null pointer checks results in a segmentation fault or access violation. This flaw operates at the application level within the terminal multiplexer's event processing pipeline, where legitimate user sessions can be disrupted through carefully crafted inputs that trigger the problematic code path. The vulnerability demonstrates characteristics consistent with CWE-476, which specifically addresses null pointer dereference conditions, and falls under the broader category of software robustness issues that can lead to denial of service conditions.
From an operational perspective, this vulnerability presents significant risks to system availability and service integrity within environments that rely on tmux for terminal session management. The denial of service impact can disrupt ongoing terminal sessions, potentially affecting multiple users in shared environments or automated processes that depend on tmux for their operation. Attackers can exploit this weakness to terminate legitimate tmux processes, forcing users to restart sessions and potentially lose unsaved work or ongoing terminal operations. The unspecified impacts mentioned in the CVE description suggest that beyond simple denial of service, the vulnerability may also enable additional attack vectors or side effects that could compromise system stability and user productivity. This vulnerability particularly affects server environments, development workstations, and any system where tmux is used for remote session management or automation tasks.
Mitigation strategies for CVE-2022-47016 should prioritize immediate patching of affected tmux installations to versions that address the null pointer dereference issue. System administrators should implement comprehensive monitoring of tmux processes to detect potential exploitation attempts and ensure proper input validation is enforced at all levels of the application stack. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service, and represents a classic example of how improper error handling can lead to system instability. Organizations should also consider implementing process isolation and resource limits for tmux sessions to minimize the impact of potential exploitation attempts. Additionally, regular security audits of terminal multiplexer configurations and user access controls should be conducted to prevent unauthorized manipulation of session parameters that could trigger the vulnerability. The remediation process should include thorough testing of patched versions to ensure that the fix does not introduce regressions in legitimate tmux functionality while maintaining the security hardening measures necessary to prevent similar issues in future development cycles.