Is CVE-2026-34872 in the CISA KEV catalog?

No. CVE-2026-34872 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34872?

CVE-2026-34872 has a CVSS v3 base score of 7.5 (Moderate).

What is the EPSS score for CVE-2026-34872?

CVE-2026-34872 has an EPSS score of 0.20% (11th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34872?

Upgrade mbedtls on debian unstable to 3.6.6-0.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-34872

MEDIUM

7.5

CVSS v3

NVD

Description

An issue was discovered in Mbed TLS 3.5.x and 3.6.x through 3.6.5 and TF-PSA-Crypto 1.0. There is a lack of contributory behavior in FFDH due to improper input validation. Using finite-field Diffie-Hellman, the other party can force the shared secret into a small set of values (lack of contributory behavior). This is a problem for protocols that depend on contributory behavior (which is not the case for TLS). The attack can be carried by the peer, or depending on the protocol by an active network attacker (person in the middle).

CWE-347

How to fix

Remediation Available

mbedtlsDebian

Fixed in:3.6.6-0.1CVE-2026-34872

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U

Exploit Intelligence

0.20%probability of exploitation in 30 days

11thpercentile

Low risk: more likely to be exploited than 11% of all known CVEs.

References

Vendor Advisory2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-03.