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CVE-2026-72398 Linux CVE debrief

A vulnerability in the Linux kernel's SCTP implementation allows for potential tampering with INIT chunks when cookie authentication is disabled. The kernel's SCTP handshake process involves the server embedding the INIT chunk into a cookie carried in INIT-ACK, which the client returns via COOKIE-ECHO. The server then unpacks and reconstructs the original INIT chunk. However, when cookie authentication is disabled, the reconstructed INIT chunk cannot be trusted and must be explicitly validated to prevent processing of tampered data. The fix adds sctp_verify_init() checks after cookie unpacking in COOKIE-ECHO processing paths when cookie authentication is disabled.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-15
Original CVE updated
2026-08-15
Advisory published
2026-08-15
Advisory updated
2026-08-15

Who should care

Linux kernel developers and maintainers, SCTP protocol implementers, and organizations using Linux-based systems with SCTP functionality should be aware of this vulnerability. They should review and apply the provided kernel patches to ensure SCTP INIT verification is performed when cookie authentication is disabled. Additionally, they should verify that SCTP cookie authentication is enabled, if possible, and monitor SCTP traffic for potential tampering attempts. Organizations using Linux-based systems with SCTP functionality should also consider implementing additional compensating controls, such as network monitoring and intrusion detection, to mitigate the vulnerability.

Technical summary

The Linux kernel's SCTP implementation is vulnerable to tampering with INIT chunks when cookie authentication is disabled. The fix adds explicit validation of INIT chunks after cookie unpacking in COOKIE-ECHO processing paths. This validation ensures that the reconstructed INIT chunk is trustworthy and prevents processing of tampered data. The vulnerability affects the Linux kernel's SCTP handshake process, specifically when cookie authentication is disabled. The fix is implemented in the COOKIE-ECHO processing paths, ensuring that INIT chunks are verified before being processed.

Defensive priority

Medium

Recommended defensive actions

  • Review and apply the provided kernel patches to ensure SCTP INIT verification is performed when cookie authentication is disabled.
  • Verify that SCTP cookie authentication is enabled, if possible.
  • Monitor SCTP traffic for potential tampering attempts.
  • Consider implementing additional compensating controls, such as network monitoring and intrusion detection.
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability. Further analysis of the Linux kernel's SCTP implementation and the provided source references is necessary to fully understand the vulnerability and its potential impact. The vulnerability allows for potential tampering with INIT chunks when cookie authentication is disabled. This could lead to processing of tampered data, potentially causing issues with SCTP connections. To verify the vulnerability, defenders should review the Linux kernel's SCTP implementation and the provided source references. They should also monitor SCTP traffic for potential tampering attempts and consider implementing additional compensating controls.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-72398 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-72398

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

  • CVE-2026-72398 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-72398

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

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/062bcbf8d1f1051fdeb20b94920031b0e2cb95a2

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/414c5447fe6a200613dd46d7fdc8454622076cb1

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/bca3100f550281c2f2418652338bced3b35af0e6

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

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.