CVE-2023-54284 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
media: av7110: prevent underflow in write_ts_to_decoder()
The buf[4] value comes from the user via ts_play(). It is a value in
the u8 range. The final length we pass to av7110_ipack_instant_repack() is "len - (buf[4] + 1) - 4" so add a check to ensure that the length is
not negative. It's not clear that passing a negative len value does anything bad necessarily, but it's not best practice.
With the new bounds checking the "if (!len)" condition is no longer possible or required so remove that.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability identified as CVE-2023-54284 resides within the Linux kernel's media subsystem, specifically affecting the av7110 driver responsible for handling digital television reception and processing. This issue manifests in the write_ts_to_decoder() function where improper input validation leads to a potential integer underflow condition. The flaw occurs when processing transport stream data from user-space applications through the ts_play() interface, where the buf[4] parameter is sourced directly from user input and constrained to the u8 data type range. The function calculates a final length value using the formula "len - (buf[4] + 1) - 4" for transmission to av7110_ipack_instant_repack(), creating a scenario where the subtraction operation could result in negative values when buf[4] exceeds the expected range relative to the initial len parameter.
The technical implementation of this vulnerability demonstrates a classic buffer management flaw that falls under the CWE-191 Integer Underflow (Wrap) category, where arithmetic operations on unsigned integers result in values that fall below the minimum representable value. The root cause stems from the absence of proper bounds checking before performing the arithmetic operation that computes the final length parameter. While the immediate impact may not necessarily result in exploitable code execution or system compromise, the underflow condition represents poor defensive programming practices that could potentially be leveraged in more complex attack scenarios or combined with other vulnerabilities. The vulnerability exposes the driver to potential instability or unpredictable behavior when malformed input data is processed, as the negative length calculation could lead to memory corruption or access violations in the underlying transport stream processing mechanisms.
The operational impact of this vulnerability extends beyond simple functional degradation to potential system reliability concerns within media processing environments. When the av7110 driver encounters malformed transport stream data with excessive buf[4] values, the resulting underflow could cause the driver to behave unpredictably during packet processing, potentially leading to data loss, stream corruption, or system instability in devices that rely on this hardware abstraction layer for digital television reception. The vulnerability affects systems utilizing the av7110 hardware decoder, which is commonly found in digital satellite receivers and set-top boxes that process DVB (Digital Video Broadcasting) transport streams. Given that the Linux kernel serves as the foundational operating system for numerous embedded devices and media processing systems, this vulnerability could impact a wide range of consumer electronics and professional broadcast equipment that depend on kernel-level media processing capabilities.
Mitigation strategies for CVE-2023-54284 focus primarily on implementing robust input validation and bounds checking within the affected kernel driver. The fix incorporates defensive programming practices by adding explicit validation to ensure that the calculated length parameter remains non-negative before proceeding with the transport stream processing operations. This approach aligns with the ATT&CK framework's defensive technique T1562.001 - "Disable or Modify Tools" and emphasizes the importance of input sanitization and parameter validation in kernel space operations. System administrators should prioritize applying the kernel patches that implement this bounds checking mechanism, as they address the root cause rather than merely mitigating symptoms. Additionally, implementing proper kernel module hardening techniques and maintaining up-to-date system firmware can provide additional layers of protection. Organizations utilizing affected hardware should conduct thorough testing of kernel updates to ensure compatibility with existing media processing workflows while also monitoring for any unusual behavior in transport stream processing that might indicate residual issues or exploitation attempts. The fix also removes redundant conditional checks that were previously deemed necessary but became obsolete due to the introduction of proper bounds validation, streamlining the code logic while improving overall system security posture.