Mbed TLS before 3.6.4 has a PEM parsing one-byte heap-based buffer underflow, in mbedtls_pem_read_buffer and two mbedtls_pk_parse functions, via untrusted PEM input.

MediumVendor CVSS 4.8 / 10 1 CVE Published Sep 3, 2026 at 1:08 AM UTC

Summary

Mariner

See the Microsoft Security Update Guide for the update that applies to your product.

Sep 3, 2026 at 1:08 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Sep 27, 2026 at 11:11 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Oct 15, 2026 at 5:20 AM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Details collected from Microsoft Security Response Center.

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