CVE-2026-53082
Description
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.
Summary dbcve.org
In the Linux kernel's net/hamradio/6pack driver, the sixpack_receive_buf() function has an uninitialized value read vulnerability. The while loop iterates through TTY error flags but fails to advance the data pointer or skip error bytes, passing potentially uninitialized data to sixpack_decode(). This causes KMSAN to detect an uninit-value read when the TTY layer provides no meaningful data for error-flagged positions.
Mitigation
Apply the upstream kernel patch that fixes sixpack_receive_buf() to process bytes one at a time, advance the data pointer on each iteration, and only pass non-error bytes to sixpack_decode(), matching the pattern used by slip_receive_buf() and mkiss_receive_buf().