Linux Kernel up to 6.6.122/6.12.68/6.18.8 mlx5e null pointer dereference

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5.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.122/6.12.68/6.18.8. It has been classified as critical. Impacted is an unknown function of the component mlx5e. The manipulation leads to null pointer dereference. This vulnerability is listed as CVE-2026-23173. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.6.122/6.12.68/6.18.8. This issue affects an unknown code block of the component mlx5e. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: TC, delete flows only for existing peers When deleting TC steering flows, iterate only over actual devcom peers instead of assuming all possible ports exist. This avoids touching non-existent peers and ensures cleanup is limited to devices the driver is currently connected to. BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 133c8a067 P4D 0 Oops: Oops: 0002 [#1] SMP CPU: 19 UID: 0 PID: 2169 Comm: tc Not tainted 6.18.0+ #156 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:mlx5e_tc_del_fdb_peers_flow+0xbe/0x200 [mlx5_core] Code: 00 00 a8 08 74 a8 49 8b 46 18 f6 c4 02 74 9f 4c 8d bf a0 12 00 00 4c 89 ff e8 0e e7 96 e1 49 8b 44 24 08 49 8b 0c 24 4c 89 ff <48> 89 41 08 48 89 08 49 89 2c 24 49 89 5c 24 08 e8 7d ce 96 e1 49 RSP: 0018:ff11000143867528 EFLAGS: 00010246 RAX: 0000000000000000 RBX: dead000000000122 RCX: 0000000000000000 RDX: ff11000143691580 RSI: ff110001026e5000 RDI: ff11000106f3d2a0 RBP: dead000000000100 R08: 00000000000003fd R09: 0000000000000002 R10: ff11000101c75690 R11: ff1100085faea178 R12: ff11000115f0ae78 R13: 0000000000000000 R14: ff11000115f0a800 R15: ff11000106f3d2a0 FS: 00007f35236bf740(0000) GS:ff110008dc809000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000157a01001 CR4: 0000000000373eb0 Call Trace: <TASK> mlx5e_tc_del_flow+0x46/0x270 [mlx5_core] mlx5e_flow_put+0x25/0x50 [mlx5_core] mlx5e_delete_flower+0x2a6/0x3e0 [mlx5_core] tc_setup_cb_reoffload+0x20/0x80 fl_reoffload+0x26f/0x2f0 [cls_flower] ? mlx5e_tc_reoffload_flows_work+0xc0/0xc0 [mlx5_core] ? mlx5e_tc_reoffload_flows_work+0xc0/0xc0 [mlx5_core] tcf_block_playback_offloads+0x9e/0x1c0 tcf_block_unbind+0x7b/0xd0 tcf_block_setup+0x186/0x1d0 tcf_block_offload_cmd.isra.0+0xef/0x130 tcf_block_offload_unbind+0x43/0x70 __tcf_block_put+0x85/0x160 ingress_destroy+0x32/0x110 [sch_ingress] __qdisc_destroy+0x44/0x100 qdisc_graft+0x22b/0x610 tc_get_qdisc+0x183/0x4d0 rtnetlink_rcv_msg+0x2d7/0x3d0 ? rtnl_calcit.isra.0+0x100/0x100 netlink_rcv_skb+0x53/0x100 netlink_unicast+0x249/0x320 ? __alloc_skb+0x102/0x1f0 netlink_sendmsg+0x1e3/0x420 __sock_sendmsg+0x38/0x60 ____sys_sendmsg+0x1ef/0x230 ? copy_msghdr_from_user+0x6c/0xa0 ___sys_sendmsg+0x7f/0xc0 ? ___sys_recvmsg+0x8a/0xc0 ? __sys_sendto+0x119/0x180 __sys_sendmsg+0x61/0xb0 do_syscall_64+0x55/0x640 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7f35238bb764 Code: 15 b9 86 0c 00 f7 d8 64 89 02 b8 ff ff ff ff eb bf 0f 1f 44 00 00 f3 0f 1e fa 80 3d e5 08 0d 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 20 89 55 RSP: 002b:00007ffed4c35638 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000055a2efcc75e0 RCX: 00007f35238bb764 RDX: 0000000000000000 RSI: 00007ffed4c356a0 RDI: 0000000000000003 RBP: 00007ffed4c35710 R08: 0000000000000010 R09: 00007f3523984b20 R10: 0000000000000004 R11: 0000000000000202 R12: 00007ffed4c35790 R13: 000000006947df8f R14: 000055a2efcc75e0 R15: 00007ffed4c35780

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-23173 since 01/13/2026. The exploitation is known to be difficult. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 299177 (Linux Distros Unpatched Vulnerability : CVE-2026-23173), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.123, 6.12.69 or 6.18.9 eliminates this vulnerability. Applying the patch 62e1d8920f6920543f4b095a65fb964448c9901d/2652e2f1253c53f9a3ce84cc972568b32c892734/fdf8437016f578f18b160c6e14f13ab96bfbc3ba/f67666938ae626cbda63fbf5176b3583c07e7124 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (299177) and CERT Bund (WID-SEC-2026-0421). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • IBM QRadar SIEM

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 299177
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-23173

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.123/6.12.69/6.18.9
Patch: 62e1d8920f6920543f4b095a65fb964448c9901d/2652e2f1253c53f9a3ce84cc972568b32c892734/fdf8437016f578f18b160c6e14f13ab96bfbc3ba/f67666938ae626cbda63fbf5176b3583c07e7124

Timelineinfo

01/13/2026 CVE reserved
02/14/2026 +32 days Advisory disclosed
02/14/2026 +0 days VulDB entry created
05/05/2026 +80 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-23173 (🔒)
GCVE (CVE): GCVE-0-2026-23173
GCVE (VulDB): GCVE-100-346043
CERT Bund: WID-SEC-2026-0421 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 02/14/2026 18:04
Updated: 05/05/2026 19:30
Changes: 02/14/2026 18:04 (58), 02/14/2026 19:43 (1), 02/16/2026 20:02 (2), 02/19/2026 13:04 (1), 03/19/2026 06:12 (11), 04/13/2026 05:34 (7), 05/05/2026 19:30 (1)
Complete: 🔍
Cache ID: 216::103

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