Vulnerability in Kernel (CVE-2026-43050)

Summary

Vulnerability in Kernel (CVE-2026-43050). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 or later.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

atm: lec: fix use-after-free in sock_def_readable()

A race condition exists between lec_atm_close() setting priv->lecd
to NULL and concurrent access to priv->lecd in send_to_lecd(),
lec_handle_bridge(), and lec_atm_send(). When the socket is freed
via RCU while another thread is still using it, a use-after-free
occurs in sock_def_readable() when accessing the socket's wait queue.

The root cause is that lec_atm_close() clears priv->lecd without
any synchronization, while callers dereference priv->lecd without
any protection against concurrent teardown.

Fix this by converting priv->lecd to an RCU-protected pointer:

Mark priv->lecd as __rcu in lec.h
Use rcu_assign_pointer() in lec_atm_close() and lecd_attach()
for safe pointer assignment
Use rcu_access_pointer() for NULL checks that do not dereference
the pointer in lec_start_xmit(), lec_push(), send_to_lecd() and
lecd_attach()
Use rcu_read_lock/rcu_dereference/rcu_read_unlock in send_to_lecd(),
lec_handle_bridge() and lec_atm_send() to safely access lecd
Use rcu_assign_pointer() followed by synchronize_rcu() in
lec_atm_close() to ensure all readers have completed before
proceeding. This is safe since lec_atm_close() is called from
vcc_release() which holds lock_sock(), a sleeping lock.
Remove the manual sk_receive_queue drain from lec_atm_close()
since vcc_destroy_socket() already drains it after lec_atm_close()
returns.

v2: S…

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-2026-43050 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-43050" on the vendor's site.

CVE-2026-43050 (Kernel)
Patched: 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 — 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 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12.

🛡️ 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 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12
```
ステージング環境で 5.10.253, 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 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":"2.6.12"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.168"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-43050 linux-lts Fixed in: 6.1.168-r0
Debian DEBIAN-CVE-2026-43050 linux Fixed in: 5.10.257-1
Ubuntu UBUNTU-CVE-2026-43050 linux