CVE-2025-52496

Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler optimizations occur. An attacker may be able to extract an AES key from a multithreaded program, or perform a GCM forgery.

CVE-2025-52496 is fixed in 13 products on 1 platform, first by DEBIAN-CVE-2025-52496, released July 4, 2025. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

7.8

high

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0021

11th percentile

Mbed TLS before 3.6.4 has a race condition in AESNI detection if certain compiler optimizations occur. An attacker may be able to extract an AES key from a multithreaded program, or perform a GCM forgery.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
libmbedcrypto1 · Ubuntu 18.04.6 LTS (bionic)	2.8.0-1ubuntu0.1~esm1	libmbedcrypto1 2.8.0-1ubuntu0.1~esm1	Jul 20, 2025
libmbedcrypto3 · Ubuntu 20.04 LTS (focal)	2.16.4-1ubuntu2+esm1	libmbedcrypto3 2.16.4-1ubuntu2+esm1	Jul 20, 2025
libmbedcrypto7 · Ubuntu 22.04.1 LTS (jammy)	2.28.0-1ubuntu0.1~esm1	libmbedcrypto7 2.28.0-1ubuntu0.1~esm1	Jul 20, 2025
libmbedcrypto7t64 · Ubuntu 24.04.5 LTS (noble)	2.28.8-1ubuntu0.1~esm1	libmbedcrypto7t64 2.28.8-1ubuntu0.1~esm1	Jul 20, 2025
libmbedtls10 · Ubuntu 18.04.6 LTS (bionic)	2.8.0-1ubuntu0.1~esm1	libmbedtls10 2.8.0-1ubuntu0.1~esm1	Jul 20, 2025
libmbedtls12 · Ubuntu 20.04 LTS (focal)	2.16.4-1ubuntu2+esm1	libmbedtls12 2.16.4-1ubuntu2+esm1	Jul 20, 2025
libmbedtls14 · Ubuntu 22.04.1 LTS (jammy)	2.28.0-1ubuntu0.1~esm1	libmbedtls14 2.28.0-1ubuntu0.1~esm1	Jul 20, 2025
libmbedtls14t64 · Ubuntu 24.04.5 LTS (noble)	2.28.8-1ubuntu0.1~esm1	libmbedtls14t64 2.28.8-1ubuntu0.1~esm1	Jul 20, 2025
libmbedx509-0 · Ubuntu 18.04.6 LTS (bionic)	2.8.0-1ubuntu0.1~esm1	libmbedx509-0 2.8.0-1ubuntu0.1~esm1	Jul 20, 2025
libmbedx509-0 · Ubuntu 20.04 LTS (focal)	2.16.4-1ubuntu2+esm1	libmbedx509-0 2.16.4-1ubuntu2+esm1	Jul 20, 2025
libmbedx509-1 · Ubuntu 22.04.1 LTS (jammy)	2.28.0-1ubuntu0.1~esm1	libmbedx509-1 2.28.0-1ubuntu0.1~esm1	Jul 20, 2025
libmbedx509-1t64 · Ubuntu 24.04.5 LTS (noble)	2.28.8-1ubuntu0.1~esm1	libmbedx509-1t64 2.28.8-1ubuntu0.1~esm1	Jul 20, 2025
mbedtls · Debian 13.5 (trixie)	3.6.4-1	DEBIAN-CVE-2025-52496	Jul 4, 2025
mbedtls · Debian 14	3.6.4-1	DEBIAN-CVE-2025-52496	Jul 4, 2025
mbedtls · opensuse-leap 16.0	3.6.6-bp160.1.1	OPENSUSE-SU-2026:21144-1	Jun 22, 2026
mbedtls-2 · opensuse-leap 16.0	2.28.10-bp160.2.1	OPENSUSE-SU-2026:21864-1	Sep 16, 2026

Details

Published
July 4, 2025
Weakness
Compiler Optimization Removal or Modification of Security-critical Code
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-52496

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