Bug 2492446 (CVE-2026-53082)

Summary: CVE-2026-53082 kernel: net: hamradio: 6pack: fix uninit-value in sixpack_receive_buf
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the 6pack hamradio driver within the Linux kernel. This vulnerability occurs because the system does not properly handle data with communication errors, causing it to process uninitialized information. An attacker with local access could potentially exploit this to gain unauthorized access to sensitive data or cause the system to become unstable.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-06-24 18:12:30 UTC 
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.
Comment 1 Mauro Matteo Cascella 2026-06-25 09:10:36 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062407-CVE-2026-53082-a080@gregkh/T