CVE-2024-26994 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
speakup: Avoid crash on very long word
In case a console is set up really large and contains a really long word (> 256 characters), we have to stop before the length of the word buffer.
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Analysis
by VulDB Data Team • 02/06/2026
The vulnerability identified as CVE-2024-26994 resides within the Linux kernel's speakup subsystem, which provides speech synthesis capabilities for users with visual impairments. This subsystem operates as a kernel module that translates text displayed on the console into audible speech, making it essential for accessibility in terminal environments. The flaw manifests when the system processes extremely long words exceeding 256 characters in length, creating a potential crash condition that could disrupt system stability and accessibility services. The issue specifically affects systems where console displays are configured with large dimensions and contain exceptionally lengthy textual elements, particularly in scenarios involving automated text generation or data processing with extended identifiers.
The technical root cause of this vulnerability stems from insufficient buffer length validation within the speakup subsystem's text processing routines. When the kernel encounters words exceeding the predefined 256-character threshold, the system fails to properly manage memory allocation for the word buffer, leading to potential buffer overflow conditions or memory corruption. This flaw operates at the kernel level, making it particularly dangerous as it can cause system crashes that affect the entire operating environment rather than just the accessibility subsystem. The vulnerability demonstrates characteristics consistent with CWE-121, which describes stack-based buffer overflow conditions, and CWE-787, which addresses out-of-bounds write operations. The lack of proper bounds checking in the console text processing pipeline creates a direct path for malicious actors to potentially exploit this condition through crafted input sequences.
The operational impact of CVE-2024-26994 extends beyond simple system crashes to affect accessibility services that millions of users depend upon for computing access. When a system encounters extremely long words in console output, the speakup subsystem may crash, forcing users to lose access to critical audio feedback mechanisms during system operation. This vulnerability particularly impacts server environments, development workstations, and systems processing large datasets where extended identifiers, file names, or data structures might exceed normal character limits. The disruption can occur during normal system operation or when processing specific input streams, making it difficult to predict and prevent. From an attacker perspective, this vulnerability could be leveraged as part of a broader exploitation strategy targeting system stability, potentially enabling denial-of-service conditions that compromise system availability and user accessibility.
Mitigation strategies for CVE-2024-26994 should focus on immediate kernel updates that implement proper buffer length validation and bounds checking within the speakup subsystem. System administrators should prioritize applying the latest kernel patches that address this specific vulnerability, as the fix typically involves implementing defensive programming practices such as character limit enforcement and proper memory management. Additionally, monitoring systems should be configured to detect unusual console text patterns that might indicate attempts to trigger this vulnerability through crafted input. Organizations utilizing accessibility services should also implement redundant accessibility solutions and ensure proper system logging to detect potential exploitation attempts. The fix aligns with ATT&CK technique T1499.004, which involves resource exhaustion attacks, by preventing the specific buffer overflow condition that could lead to system instability. Regular security audits of kernel modules and accessibility subsystems should be conducted to identify similar vulnerabilities that might exist in other components of the system infrastructure.