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Vulnerabilities

Vulnerability · CVE-2026-5188

An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates.

Published Apr 10, 2026 · catalog updated Jun 17, 2026 · An integer underflow issue

Check if you run it

No confirmed exploitation is on record for CVE-2026-5188. EPSS is 0.22%. Act only if a listed version of An integer underflow issue is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (An integer underflow issue).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low2.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.22%
Remediation
Not established
Affected products
cpe wolfssl/wolfssl

An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This results in incorrect handling of certificate data. The issue is limited to configurations using the original ASN.1 parsing implementation which is off by default.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe wolfssl/wolfsslversion unspecified

How to fix CVE-2026-5188

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-5188. EPSS is 0.22%. Act only if a listed version of An integer underflow issue is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-191: Integer Underflow. EPSS 0.22%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 10, 2026 · NIST NVD

    Detected

    An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This results in incorrect handling of certificate data. The issue is limited to configurations using the original ASN.1 parsin

  2. Jun 17, 2026 · NIST NVD

    Updated

    An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This results in incorrect handling of certificate data. The issue is limited to configurations using the original ASN.1 parsin

Sources

  • CVE.orgVulnerability recordCVE-2026-5188

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-5188

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-5188

    An integer underflow issue exists in wolfSSL when parsing the Subject Alternative Name (SAN) extension of X.509 certificates. A malformed certificate can specify an entry length larger than the enclosing sequence, causing the internal length counter to wrap during parsing. This r

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.