How to Fix CVE-2026-3833: the affected product (Bundle Sibling)

By Sai Kiran Pandrala

Last verified: 2026-05-25

CVE-2026-3833 is a sibling vulnerability in the same vendor advisory as CVE-2026-33845. Applying the patched build named in the primary write-up closes this CVE as well.

What's different about CVE-2026-3833?

A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of nameConstraints labels, specifically for dNSName (DNS) or rfc822Name (email) constraints within excludedSubtrees or permittedSubtrees. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.

The technical impact and remediation are identical to the primary CVE in the bundle. The same vendor patch closes both.

How to fix CVE-2026-3833

Apply the patched build per the primary write-up: How to Fix CVE-2026-33845.

The patch installation procedure, verification commands, and interim mitigations are documented there. Reusing one runbook keeps the rollout consistent across the bundle.

Frequently asked questions

Is CVE-2026-3833 fixed by the same patch as CVE-2026-33845?

Yes. CVE-2026-3833 ships in the same vendor advisory as CVE-2026-33845. Applying the patched build named in the primary write-up closes both.

What is the CVSS score for CVE-2026-3833?

The CVSS base score is 6.5 (Medium).

Is it being exploited?

It is not currently listed in CISA KEV.

References

• Official vendor advisory: https://access.redhat.com/errata/RHSA-2026:13274
• NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-3833
• CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
• Primary write-up: How to Fix CVE-2026-33845

*Part of the the affected product bundle. Full procedure at CVE-2026-33845.*