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PatchSiren cyber security CVE debrief

CVE-2024-27436 Linux CVE debrief

A vulnerability in the Linux kernel's ALSA USB audio driver could allow a local attacker to cause a denial of service. The flaw occurs when parsing channel bits from USB audio devices that set more bits than the declared number of channels, potentially causing an out-of-bounds write to the channel map array. This affects Siemens SIMATIC S7-1500 TM MFP industrial control systems that include a GNU/Linux subsystem. The vulnerability requires local access and low privileges to exploit, with no confidentiality or integrity impact but high availability impact.

Vendor
Linux
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2024-04-09
Original CVE updated
2026-05-14
Advisory published
2024-04-09
Advisory updated
2026-05-14

Who should care

Organizations operating Siemens SIMATIC S7-1500 TM MFP industrial control systems with the GNU/Linux subsystem enabled should prioritize this vulnerability. System administrators responsible for ICS/OT environments, security teams managing industrial assets, and personnel with access to the embedded Linux shell on affected devices are the primary stakeholders. The vulnerability is particularly relevant in environments where USB devices may connect to the industrial system.

Technical summary

The vulnerability exists in the ALSA (Advanced Linux Sound Architecture) USB audio driver within the Linux kernel. When parsing channel configuration bits from a USB audio device, the driver fails to validate that the number of bits set does not exceed the declared channel count. A malicious or malformed USB audio device can set more channel bits than the allocated map array size, resulting in an out-of-bounds write. This is classified as CWE-20 (Improper Input Validation). The vulnerability was fixed by stopping channel bit parsing once all expected channels are found, preventing the overflow condition.

Defensive priority

medium

Recommended defensive actions

  • Limit access to the interactive shell of the additional GNU/Linux subsystem to trusted personnel only
  • Only build and run applications from trusted sources
  • Monitor for kernel updates from Siemens for the SIMATIC S7-1500 TM MFP GNU/Linux subsystem
  • Apply defense-in-depth strategies for industrial control systems per CISA guidance

Evidence notes

The vulnerability was disclosed in the Linux kernel ALSA USB audio subsystem. CISA published advisory ICSA-24-102-01 on 2024-04-09, with subsequent updates through 2025-09-09 adding additional CVEs to the same advisory. Siemens published security advisory SSA-265688 covering this vulnerability in their SIMATIC S7-1500 TM MFP product. The CVSS 3.1 vector confirms local attack vector with low attack complexity.

Sources and references

Verified primary and authoritative sources

  • CVE-2024-27436 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2024-27436

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2024-27436 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2024-27436

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2024/icsa-24-102-01.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-265688.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-265688.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-24-102-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-alerts/ics-alert-10-301-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/resources-tools/resources/ics-recommended-practices

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/topics/industrial-control-systems

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf

    Reference

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.