How to Fix CVE-2026-28390: OpenSSL (Bundle Sibling)
*By Sai Kiran Pandrala*
Last verified: 2026-05-25
| Severity | CVSS 7.5, High |
|---|---|
| Actively exploited? | No |
| Affected | OpenSSL (3.6.0 < 3.6.2, 3.5.0 < 3.5.6) |
| Fixed in | Same patched build as CVE-2026-28386 |
| Type (CWE) | CWE-476: NULL Pointer Dereference |
CVE-2026-28390 is a sibling vulnerability in the same Openssl OpenSSL advisory bundle as CVE-2026-28386. The same patched build closes every CVE in the bundle, so the remediation procedure for CVE-2026-28390 matches the primary write-up.
What is different about CVE-2026-28390?
Issue summary: During processing of a crafted CMS EnvelopedData message
with KeyTransportRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may
crash before authentication or cryptographic operations occur resulting in
Denial of Service. When a CMS EnvelopedData message that uses KeyTransportRecipientInfo with
RSA-OAEP encryption is processed, the optional parameters field of
RSA-OAEP SourceFunc algorithm identifier is e...
Impact is consistent with the bundle: a denial-of-service condition that crashes or hangs the affected service. The patched build closes every code path in the advisory in one update.
How to fix CVE-2026-28390
Apply the patched build per the primary write-up: How to Fix CVE-2026-28386.
For a quick check, confirm the running version of OpenSSL:
openssl version
Frequently asked questions
Is CVE-2026-28390 being actively exploited?
Not at the time of writing. It is not listed in CISA's Known Exploited Vulnerabilities catalog. That status can change, so monitor the vendor advisory and the KEV catalog if the system is exposed.
How severe is CVE-2026-28390?
CVSS rates it 7.5 (High). Use that score to set your patch priority alongside the other items in your queue.
Do I have to take OpenSSL offline to apply the patch?
It depends on the deployment. High-availability or clustered installs can usually patch one node at a time with no full outage. Standalone installs typically need a short restart. Always follow the vendor's documented upgrade steps.
What if my vulnerability scanner still flags CVE-2026-28390 after I patch?
Re-run the scan after a service restart, then confirm the scanner's plugin set is up to date. Some scanners detect by banner version only and lag the official fix metadata by a release.
References
- Official vendor advisory: https://openssl-library.org/news/secadv/20260407.txt
- NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2026-28390
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary write-up: How to Fix CVE-2026-28386
*Written by Sai Kiran Pandrala. Last verified 2026-05-25. Part of the Openssl OpenSSL advisory bundle. Full procedure at how-to-fix-cve-2026-28386.*