CVE-2026-53082
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In the 6pack (hamradio) driver in the Linux kernel, the sixpack_receive_buf() function does not skip bytes with TTY error flags, leading to processing of uninitialized data and KMSAN reporting an uninit-value read.
Risk Assessment
The risk includes potential disclosure of sensitive data or system instability due to processing erroneous data in the 6pack protocol.
Recommendation
It is recommended to update the Linux kernel to a version containing the fix that processes bytes one at a time and skips bytes with TTY error flags.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: net: hamradio: 6pack: fix uninit-value in sixpack_receive_buf sixpack_receive_buf() does not properly skip bytes with TTY error flags. The while loop iterates through the flags buffer but never advances the data pointer (cp), and passes the original count (including error bytes) to sixpack_decode(). This causes sixpack_decode() to process bytes that should have been skipped due to TTY errors. The TTY layer does not guarantee that cp[i] holds a meaningful value when fp[i] is set, so passing those positions to sixpack_decode() results in KMSAN reporting an uninit-value read. Fix this by processing bytes one at a time, advancing cp on each iteration, and only passing valid (non-error) bytes to sixpack_decode(). This matches the pattern used by slip_receive_buf() and mkiss_receive_buf() for the same purpose.