How severe is CVE-2025-66442?

CVE-2025-66442 has a CVSS 3.x base score of 5.1, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-66442 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66442?

CVE-2025-66442 primarily affects Arm Mbed Tls. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-66442?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-66442 have an EU (EUVD) identifier?

Yes. CVE-2025-66442 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-209171.

When was CVE-2025-66442 published?

CVE-2025-66442 was published on 2026-04-01 and last updated on 2026-06-17.

CVE-2025-66442

CVE-2025-66442 is a medium-severity vulnerability in Arm Mbed Tls with a CVSS 3.x base score of 5.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-385.

Key facts

Severity: Medium (CVSS 3.x base score 5.1)
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-209171
Weakness: CWE-385
Affected product: Arm Mbed Tls
Published: 2026-04-01
Last modified: 2026-06-17

Description

In Mbed TLS through 4.0.0, there is a compiler-induced timing side channel (in RSA and CBC/ECB decryption) that only occurs with LLVM's select-optimize feature. TF-PSA-Crypto through 1.0.0 is also affected.

Frequently asked questions

What is CVE-2025-66442?: In Mbed TLS through 4.0.0, there is a compiler-induced timing side channel (in RSA and CBC/ECB decryption) that only occurs with LLVM's select-optimize feature. TF-PSA-Crypto through 1.0.0 is also affected.
How severe is CVE-2025-66442?: CVE-2025-66442 has a CVSS 3.x base score of 5.1, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-66442 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66442?: CVE-2025-66442 primarily affects Arm Mbed Tls. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-66442?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66442 have an EU (EUVD) identifier?: Yes. CVE-2025-66442 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-209171.
When was CVE-2025-66442 published?: CVE-2025-66442 was published on 2026-04-01 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*
cpe:2.3:a:arm:tf-psa-crypto:*:*:*:*:*:*:*:*

More vulnerabilities in Arm Mbed Tls

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