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CVE-2026-98455

Vulnerability in Linux kernel (CVE-2026-98455)

Summary

Vulnerability in Linux kernel (CVE-2026-98455). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

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

Bluetooth: RFCOMM: fix NULL dereference of dlc->session in RFCOMM_CONNINFO

The RFCOMM_CONNINFO getsockopt handler accepts a socket that is not
connected as long as deferred setup is enabled:

if (sk->sk_state != BT_CONNECTED &&
			!rfcomm_pi(sk)->dlc->defer_setup) {
	err = -ENOTCONN;
	break;
}
l2cap_sk = rfcomm_pi(sk)->dlc->session->sock->sk;

dlc->defer_setup is set in rfcomm_sock_init() when rfcomm_connect_ind()
creates a child socket for an incoming connection on a listening socket
that has BT_DEFER_SETUP enabled. It is never cleared afterwards. The
session, however, can go away underneath it.

rfcomm_recv_disc() forces the dlc state before tearing it down:

d->state = BT_CLOSED;
__rfcomm_dlc_close(d, err);

The RFCOMM_DEFER_SETUP early return in __rfcomm_dlc_close() only covers
BT_CONNECT, BT_CONFIG, BT_OPEN and BT_CONNECT2, so with the state
already BT_CLOSED that switch does not match and the function falls
through to rfcomm_dlc_unlink(), which sets d->session = NULL, while
d->defer_setup stays 1.

A getsockopt(SOL_RFCOMM, RFCOMM_CONNINFO) on the accepted socket after
that point therefore skips the -ENOTCONN path -- sk->sk_state is
BT_CLOSED, but dlc->defer_setup is still set -- and dereferences the
NULL session. No race is needed: once the DISC has been processed, the
dereference is unconditional.

Reproduced on a KASAN kernel under QEMU with a BR/EDR peer emulated over
/dev/vhci: the peer br…

Source: NIST National Vulnerability Database NVD GitHub Advisory

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-2026-98455 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-98455" on the vendor's site.

CVE-2026-98455 (Linux kernel)
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 Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

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

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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. Audit SBOM/dependencies to find affected services.

Response actions

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

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    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。

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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