dbcve.org
OpenSSLFramework / library

CVE-2026-42767

MEDIUM · 5.9 CVSS v3.1 Published 2026-06-09
Fix available
A fix is available. Upgrade to 3.0.21 / 3.4.6 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Issue summary: An attacker-controlled CMP (Certificate Management Protocol) server could trigger a NULL pointer dereference in a CMP client application. Impact summary: A NULL pointer dereference causes a crash of the application and a Denial of Service. An attacker controlling a CMP server (or acting as a man-in-the-middle) could craft a CMP response containing a CRMF (Certificate Request Message Format) CertRepMessage with an EncryptedValue structure where the symmAlg field has an algorithm OID but no parameters field. When the OpenSSL CMP client processes this response, the NULL dereference occurs, causing a crash of the CMP client. Applications that process untrusted CMP/CRMF messages may be affected. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-476

The code follows a pointer that is null, crashing the process. An attacker who can reliably trigger it turns the crash into a denial of service. The fix is checking for null before use and handling the failure path gracefully.

General guidance for the null pointer dereference class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OpenSSLFramework / library
Affected:>= 3.0.0, < 3.0.21>= 3.4.0, < 3.4.6>= 3.5.0, < 3.5.7>= 3.6.0, < 3.6.3= 4.0.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.0.21 / 3.4.6 / 3.5.7 or later
Fixed in 3.0.213.4.63.5.7
Vendor patch github.com →
Recommended fix High confidence

OpenSSL 3.0.21, 3.4.6, 3.5.7, or 3.6.3 (depending on your current minor version branch)

  1. 1. Identify the currently installed OpenSSL version using 'openssl version -a' or checking your package manager.
  2. 2. Determine which branch of OpenSSL 3.x you are currently using (3.0.x, 3.4.x, 3.5.x, or 3.6.x).
  3. 3. If running 3.0.x: Upgrade to OpenSSL 3.0.21 or later.
  4. 4. If running 3.4.x: Upgrade to OpenSSL 3.4.6 or later.
  5. 5. If running 3.5.x: Upgrade to OpenSSL 3.5.7 or later.
  6. 6. If running 3.6.x: Upgrade to OpenSSL 3.6.3 or later.
  7. 7. After upgrading, verify the new version is installed using 'openssl version -a'.
  8. 8. Restart any services or applications that use OpenSSL to ensure they load the updated library.
Caveat Minor version upgrades within the same branch (e.g., 3.0.0 to 3.0.21) typically have minimal breaking changes; however, review the release notes for any behavior changes.

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,850. Get the upgrade done

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-42767 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42767 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data