BusyBox TFTP client heap overflow (CVE-2026-124737)
CVE-2026-124737 Published on November 11, 2026
Busybox: heap buffer overflow in the tftp client on fallback to the default block size
A flaw was found in BusyBox. When the TFTP (Trivial File Transfer Protocol) client requests a custom small block size and receives a standard response, it falls back to the default block size without resizing the allocated memory buffer. A malicious TFTP server can exploit this issue by sending standard-sized network packets during a transfer, causing a heap buffer overflow. This flaw allows an attacker to achieve arbitrary code execution or cause a Denial of Service (DoS) by crashing the application.
Vulnerability Analysis
CVE-2026-124737 can be exploited with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Timeline
Reported to Red Hat.
Made public. 17 days later.
Weakness Type
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-124737 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-124737
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