How severe is CVE-2026-5393?

CVE-2026-5393 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2026-5393 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-2026-5393?

CVE-2026-5393 affects Wolfssl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5393?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-5393 have an EU (EUVD) identifier?

Yes. CVE-2026-5393 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21231.

When was CVE-2026-5393 published?

CVE-2026-5393 was published on 2026-04-10 and last updated on 2026-06-17.

CVE-2026-5393

CVE-2026-5393 is a critical-severity vulnerability in Wolfssl with a CVSS 3.x base score of 9.1. 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-125.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v4: 6.3
EPSS exploit prediction: 0% (9th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21231
Weakness: CWE-125
Affected product: Wolfssl
Published: 2026-04-10
Last modified: 2026-06-17

Description

Dual-Algorithm CertificateVerify out-of-bounds read. When processing a dual-algorithm CertificateVerify message, an out-of-bounds read can occur on crafted input. This can only occur when --enable-experimental and --enable-dual-alg-certs is used when building wolfSSL.

Frequently asked questions

What is CVE-2026-5393?: Dual-Algorithm CertificateVerify out-of-bounds read. When processing a dual-algorithm CertificateVerify message, an out-of-bounds read can occur on crafted input. This can only occur when --enable-experimental and --enable-dual-alg-certs is used when building wolfSSL.
How severe is CVE-2026-5393?: CVE-2026-5393 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2026-5393 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-2026-5393?: CVE-2026-5393 affects Wolfssl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5393?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-5393 have an EU (EUVD) identifier?: Yes. CVE-2026-5393 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21231.
When was CVE-2026-5393 published?: CVE-2026-5393 was published on 2026-04-10 and last updated on 2026-06-17.

References

https://github.com/wolfSSL/wolfssl/pull/10079

Affected products (1)

cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*

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