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PatchSiren cyber security CVE debrief

CVE-2026-25832 TrustedFirmware CVE debrief

A low-severity vulnerability exists in Mbed TLS 3.6.x before 3.6.7 and 4.1.x before 4.1.2, where the TLS 1.3 client accepts HelloRetryRequest selecting an unadvertised group. This issue has a CVSS score of 3.7. The vulnerability may allow for information disclosure. Defenders should verify configurations and consider updates to mitigate potential risks. Verification of Mbed TLS versions and configurations is necessary to ensure secure TLS 1.3 client interactions. Updating to Mbed TLS versions 3.6.7 or 4.1.2 may be necessary to address the vulnerability.

Vendor
TrustedFirmware
Product
Mbed TLS
CVSS
LOW 3.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-14
Original CVE updated
2026-09-22
Advisory published
2026-09-14
Advisory updated
2026-09-22

Who should care

Defenders responsible for Mbed TLS configurations and TLS 1.3 client deployments should assess exposure and consider updates to mitigate potential risks.

Why it matters

CVE-2026-25832 is a low-severity vulnerability in Mbed TLS that may allow for information disclosure. Defenders should verify configurations and consider updates.

  • Verification of Mbed TLS versions and configurations is necessary to ensure secure TLS 1.3 client interactions.
  • Updating to Mbed TLS versions 3.6.7 or 4.1.2 may be necessary to address the vulnerability.

Technical summary

The TLS 1.3 client in Mbed TLS 3.6.x before 3.6.7 and 4.1.x before 4.1.2 accepts HelloRetryRequest selecting an unadvertised group, allowing for potential information disclosure. This issue has a CVSS score of 3.7. The vulnerability affects Mbed TLS configurations and TLS 1.3 client deployments. Defenders should assess exposure and consider updates to mitigate potential risks.

Defensive priority

Defenders should prioritize verifying Mbed TLS versions and configurations, especially for TLS 1.3 clients, and consider updating to versions 3.6.7 or 4.1.2.

Recommended defensive actions

  • Verify Mbed TLS versions and configurations for TLS 1.3 clients
  • Consider updating to Mbed TLS versions 3.6.7 or 4.1.2
  • Review and adjust TLS 1.3 client settings as necessary

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability. Mbed TLS documentation is referenced for further details. The vulnerability was disclosed on 2026-09-14T07:17:16.490Z. The CVE record has not been modified since then. Defenders should consult the official CVE Program record and NIST NVD detail page for additional information.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-25832 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-25832

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

  • CVE-2026-25832 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-25832

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

Supplemental references

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.