How severe is CVE-2026-5500?

CVE-2026-5500 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-5500 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-5500?

CVE-2026-5500 affects Wolfssl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-5500?

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

Does CVE-2026-5500 have an EU (EUVD) identifier?

Yes. CVE-2026-5500 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21293.

When was CVE-2026-5500 published?

CVE-2026-5500 was published on 2026-04-10 and last updated on 2026-06-17.

CVE-2026-5500

CVE-2026-5500 is a medium-severity vulnerability in Wolfssl with a CVSS 3.x base score of 5.9. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v4: 8.7
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-21293
Weakness: CWE-20
Affected product: Wolfssl
Published: 2026-04-10
Last modified: 2026-06-17

Description

wolfSSL's wc_PKCS7_DecodeAuthEnvelopedData() does not properly sanitize the AES-GCM authentication tag length received and has no lower bounds check. A man-in-the-middle can therefore truncate the mac field from 16 bytes to 1 byte, reducing the tag check from 2⁻¹²⁸ to 2⁻⁸.

Frequently asked questions

What is CVE-2026-5500?: wolfSSL's wc_PKCS7_DecodeAuthEnvelopedData() does not properly sanitize the AES-GCM authentication tag length received and has no lower bounds check. A man-in-the-middle can therefore truncate the mac field from 16 bytes to 1 byte, reducing the tag check from 2⁻¹²⁸ to 2⁻⁸.
How severe is CVE-2026-5500?: CVE-2026-5500 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-5500 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-5500?: CVE-2026-5500 affects Wolfssl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-5500?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-5500 have an EU (EUVD) identifier?: Yes. CVE-2026-5500 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-21293.
When was CVE-2026-5500 published?: CVE-2026-5500 was published on 2026-04-10 and last updated on 2026-06-17.

References

https://github.com/wolfSSL/wolfssl/pull/10102

Affected products (1)

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

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