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CVE-2024-26903 medium CVSS 5.5

Vulnerability in Linux kernel (CVE-2024-26903)

Summary

Vulnerability in Linux kernel (CVE-2024-26903). Risk of unauthorized operations or information disclosure. Exploitable via HCI_CMD.

Original description

The description as published by the source.

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

Bluetooth: rfcomm: Fix null-ptr-deref in rfcomm_check_security

During our fuzz testing of the connection and disconnection process at the
RFCOMM layer, we discovered this bug. By comparing the packets from a
normal connection and disconnection process with the testcase that
triggered a KASAN report. We analyzed the cause of this bug as follows:

  1. In the packets captured during a normal connection, the host sends a
    Read Encryption Key Size type of HCI_CMD packet
    (Command Opcode: 0x1408) to the controller to inquire the length of
    encryption key.After receiving this packet, the controller immediately
    replies with a Command Completepacket (Event Code: 0x0e) to return the
    Encryption Key Size.

  2. In our fuzz test case, the timing of the controller's response to this
    packet was delayed to an unexpected point: after the RFCOMM and L2CAP
    layers had disconnected but before the HCI layer had disconnected.

  3. After receiving the Encryption Key Size Response at the time described
    in point 2, the host still called the rfcomm_check_security function.
    However, by this time struct l2cap_conn *conn = l2cap_pi(sk)->chan->conn;
    had already been released, and when the function executed
    return hci_conn_security(conn->hcon, d->sec_level, auth_type, d->out);,
    specifically when accessing conn->hcon, a null-ptr-deref error occurred.

To fix this bug, check if sk->sk_state is BT_CLOSED before calling
rfcomm_recv_frame…

Source: GitHub Security Advisories (Global) 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-2024-26903 has been found in Linux kernel.
Attackers can target a specific entry point like HCI_CMD over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2024-26903" on the vendor's site.

CVE-2024-26903 (Linux kernel) — CWE-476 / CVSS v3 5.5
Attack vector: local / no user interaction
Attack surface: HCI_CMD
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 (CWE-476) exists in Linux kernel. Attackers reach the vulnerable code path via HCI_CMD.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel. Attack surface: HCI_CMD.

🔥 Severity

Severity: Medium (CVSS 5.5/10). 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。

Affected packages

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.12"},{"fixed":"4.19.311"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.273"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.214"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.153"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.83"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.23"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.7.11"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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