CVE-2026-43085

netfilter: nfnetlink_log: initialize nfgenmsg in NLMSG_DONE terminator

MEDIUM
5.5
CVSS Score
Published: May 6, 2026 at 07:40 AM UTC
Updated: October 15, 2026 at 02:19 AM UTC
4 products affected across 2 vendorsLinux KernelSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP FirmwareSiplus S7-1500 CPU 1518-4 Pn /dp MFP Firmware

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.6.23.1 ≤ v < 5.10.2585.11 ≤ v < 5.15.2095.16 ≤ v < 6.1.1756.13 ≤ v < 6.18.246.19 ≤ v < 6.19.146.2 ≤ v < 6.6.1366.7 ≤ v < 6.12.832.6.2329c5d4afba51c71cfeadd3f74f3c42e064483fb07.07.0 rc17.0 rc27.0 rc37.0 rc47.0 rc57.0 rc67.0 rc7
Vendor states this is fixed in 15d209bccf9273b4a8b4e579ba0e92d065b6ec8c (fixed)
Vendor states this is fixed in 1f3083aec8836213da441270cdb1ab612dd82cf4 (fixed)
Vendor states this is fixed in 296f18e1c3a87c915a92ed27832d5040a22d1072 (fixed)
Vendor states this is fixed in 368c22aea490f6f50df831b4f9e3623787686c5b (fixed)
Vendor states this is fixed in 57cc509d82b46150a11dcecc8b25eaa177eda34d (fixed)
Vendor states this is fixed in 9e2182865de781c41ab16b7985e9d26dcefea867 (fixed)
Vendor states this is fixed in d1399632ba255d2e02c757af5d9f5d9279ce168c (fixed)
Vendor states this is fixed in d552bcfca323d175664d7444989b04f55666978a (fixed)
Vendor states this is fixed in 2.6.23 (unaffected)
Vendor states this is fixed in 5.10.258 (unaffected)
Vendor states this is fixed in 5.15.209 (unaffected)
Vendor states this is fixed in 6.1.175 (unaffected)
Vendor states this is fixed in 6.12.83 (unaffected)
Vendor states this is fixed in 6.18.24 (unaffected)
Vendor states this is fixed in 6.19.14 (unaffected)
Vendor states this is fixed in 6.6.136 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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