Bug 2467020 (CVE-2026-43085) - CVE-2026-43085 kernel: netfilter: nfnetlink_log: initialize nfgenmsg in NLMSG_DONE terminator
Summary: CVE-2026-43085 kernel: netfilter: nfnetlink_log: initialize nfgenmsg in NLMSG...
Keywords:
Status: NEW
Alias: CVE-2026-43085
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-06 10:03 UTC by OSIDB Bzimport
Modified: 2026-05-06 13:27 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-05-06 10:03:30 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfilter: nfnetlink_log: initialize nfgenmsg in NLMSG_DONE terminator

When batching multiple NFLOG messages (inst->qlen > 1), __nfulnl_send()
appends an NLMSG_DONE terminator with sizeof(struct nfgenmsg) payload via
nlmsg_put(), but never initializes the nfgenmsg bytes. The nlmsg_put()
helper only zeroes alignment padding after the payload, not the payload
itself, so four bytes of stale kernel heap data are leaked to userspace
in the NLMSG_DONE message body.

Use nfnl_msg_put() to build the NLMSG_DONE terminator, which initializes
the nfgenmsg payload via nfnl_fill_hdr(), consistent with how
__build_packet_message() already constructs NFULNL_MSG_PACKET headers.


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