How severe is CVE-2026-34871?

CVE-2026-34871 has a CVSS 3.x base score of 6.7, 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 high, and availability none.

Is CVE-2026-34871 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34871?

CVE-2026-34871 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-2026-34871?

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

Does CVE-2026-34871 have an EU (EUVD) identifier?

Yes. CVE-2026-34871 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18001.

When was CVE-2026-34871 published?

CVE-2026-34871 was published on 2026-04-01 and last updated on 2026-06-17.

CVE-2026-34871

CVE-2026-34871 is a medium-severity vulnerability in Arm Mbed Tls with a CVSS 3.x base score of 6.7. 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-338.

Key facts

Severity: Medium (CVSS 3.x base score 6.7)
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18001
Weakness: CWE-338
Affected product: Arm Mbed Tls
Published: 2026-04-01
Last modified: 2026-06-17

Description

An issue was discovered in Mbed TLS before 3.6.6 and 4.x before 4.1.0 and TF-PSA-Crypto before 1.1.0. There is a Predictable Seed in a Pseudo-Random Number Generator (PRNG).

Frequently asked questions

What is CVE-2026-34871?: An issue was discovered in Mbed TLS before 3.6.6 and 4.x before 4.1.0 and TF-PSA-Crypto before 1.1.0. There is a Predictable Seed in a Pseudo-Random Number Generator (PRNG).
How severe is CVE-2026-34871?: CVE-2026-34871 has a CVSS 3.x base score of 6.7, 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 high, and availability none.
Is CVE-2026-34871 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34871?: CVE-2026-34871 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-2026-34871?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-34871 have an EU (EUVD) identifier?: Yes. CVE-2026-34871 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18001.
When was CVE-2026-34871 published?: CVE-2026-34871 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:trustedfirmware:tf-psa-crypto:*:*:*:*:*:*:*:*

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