Vulnerability in Kernel (CVE-2026-23173)

Summary

Vulnerability in Kernel (CVE-2026-23173). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.6.123, 6.12.69, 6.18.9 or later.

Original description

The description as published by the source.

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: 0000…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-23173 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.6.123, 6.12.69, 6.18.9 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-23173" on the vendor's site.

CVE-2026-23173 (Kernel)
Patched: 6.6.123, 6.12.69, 6.18.9 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 6.6.123, 6.12.69, 6.18.9.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Kernel' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'Kernel' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Kernel を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade Kernel to 6.6.123, 6.12.69, 6.18.9
```
ステージング環境で 6.6.123, 6.12.69, 6.18.9 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"6.5.0"},{"fixed":"6.6.123"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.69"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.9"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-23173 linux-lts Fixed in: 6.12.73-r0
Debian DEBIAN-CVE-2026-23173 linux Fixed in: 6.12.69-1
Ubuntu UBUNTU-CVE-2026-23173 linux-hwe-edge