Invalid Pointer Dereference in CMP Server via Crafted protectionAlg (CVE-2026-63076)

What is affected, what to do

A flaw was found in OpenSSL. A crafted CMP (Certificate Management Protocol) message can cause an invalid pointer dereference due to a missing type check in the password-based protection verification.

Update OpenSSL to version 4.0.2, OpenSSL to version 3.6.4, OpenSSL to version 3.5.8.

Affected

• OpenSSL lt 4.0.0..4.0.2
• OpenSSL lt 3.6.0..3.6.4
• OpenSSL lt 3.5.0..3.5.8
• OpenSSL lt 3.4.0..3.4.7
• OpenSSL lt 3.0.0..3.0.22

Fixed in

• OpenSSL 4.0.2
• OpenSSL 3.6.4
• OpenSSL 3.5.8
• OpenSSL 3.4.7
• OpenSSL 3.0.22

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Metrics

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2

NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

Read in glossary

High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.

CRA

The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

Read in glossary

From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.

ISO/IEC 27001

ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

Read in glossary

Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

A flaw was found in OpenSSL. A crafted CMP (Certificate Management Protocol) message can cause an invalid pointer dereference due to a missing type check in the password-based protection verification. A remote, unauthenticated attacker can crash applications acting as a CMP server or client, resulting in a denial of service.

Source: redhat_csaf, suse_csaf, Ubuntu Security Notices, Debian Security Advisories, Microsoft Security Update Guide, Debian LTS Advisories, NVD (NIST), cvelistv5, BSI WID Portal, BSI CSAF

Vendors and products

• Debian Openssl
• Freebsd Project Freebsd OS
• Meinberg Lantime
• Open Source Openssl
• OpenSSL OpenSSL
• Ubuntu Openssl

Weakness classes (CWE)

• CWE-476NULL Pointer Dereference

  Base

  The product dereferences a pointer that it expects to be valid but is NULL.

  Entry at MITRE CWE-476

References & sources

• openssl-library.orgOpenSSL AdvisoryVendor advisory
• github.com4.0.2 git commitPatch
• github.com3.6.4 git commitPatch
• github.com3.5.8 git commitPatch
• github.com3.4.7 git commitPatch
• github.com3.0.22 git commitPatch

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

1. 11.09.2026Initial analysis by NVDNVD

   Newly listed as affected:

   • OpenSSL (3.5.0 – before 3.5.8; 3.6.0 – before 3.6.4; 4.0.0 – before 4.0.2; 3.4.0 – before 3.4.7; 3.0.0 – before 3.0.22)

   New references:

   • https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b
   • https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e
   • https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259
   • https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226

   and 2 more references

   Show 7 original changes

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   Product configuration	added	—	OR *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.5.0 up to (excluding) 3.5.8 *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.6.0 up to (excluding) 3.6.4 *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 4.0.0 up to (excluding) 4.0.2 *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.4.0 up to (excluding) 3.4.7 *cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* versions from (including) 3.0.0 up to (excluding) 3.0.22
   Reference type	added	—	OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b Types: Patch
   Reference type	added	—	OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e Types: Patch
   Reference type	added	—	OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259 Types: Patch
   Reference type	added	—	OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226 Types: Patch
   Reference type	added	—	OpenSSL Software Foundation: https://github.com/openssl/openssl/commit/cdacfff557389abfa9e4615abded2ec984517d6c Types: Patch
   Reference type	added	—	OpenSSL Software Foundation: https://openssl-library.org/news/secadv/20260825.txt Types: Vendor Advisory

   Source identifier: nvd@nist.gov

2. 25.08.2026Record modifiedCISA ADP

   CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

   CISA assessment (SSVC): exploitation: none known, automatable: yes

   Show 2 original changes

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   CVSS	added	—	AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
   SSVC assessment	added	—	{"id":"CVE-2026-63076","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-08-25T14:37:28.943884Z"}

   Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

3. 25.08.2026Receivedopenssl.org

   Weakness type: CWE-476

   Description added or changed

   New references:

   • https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b
   • https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e
   • https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259
   • https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226

   and 2 more references

   Show 9 original changes

   Individual changes of this event as published by NVD

   Type	Action	Before	After
   Affected versions (publisher)	added	—	OpenSSL
   Description	added	—	Issue summary: OpenSSL CMP password based protection verification only checks whether the protectionAlg parameter was not NULL and not its ASN.1 type, before treating it as a PBMParameter. A crafted message can contain a parameter of a different type, which is then dereferenced as an invalid pointer. Impact summary: A remote, unauthenticated attacker can crash an application acting as a CMP server that accepts PBM-protected messages, or a CMP client talking to a malicious or intercepted CMP server, resulting in a Denial of Service. CWE: CWE-476: NULL Pointer Dereference Description: When verifying the password-based MAC protection of a CMP message, OpenSSL library reads the protectionAlg algorithm parameter with X509_ALGOR_get0(), which returns both the parameter type and its value pointer. The value is then cast to an ASN1_STRING and treated as the expected PBMParameter after only checking that pointer is not NULL. The parameter type returned by X509_ALGOR_get0() was never consulted. This happens during protection verification, before any MAC is computed, so no knowledge of the PBM shared secret is required; the only precondition is that PBM verification is reachable. On the server side this is reached from OSSL_CMP_SRV_process_request() for any application that stands up a CMP server accepting PBM-protected messages, and on the client side from CMP response validation against a malicious or on-path (MITM) server. The reliable consequence is a denial of service; there is no memory disclosure, no controlled memory write, and no path to code execution. CMP is a specialized feature that an application must explicitly enable. FIPS impact: no As the CMP code lives outside the FIPS module boundary, no FIPS modules are affected by this CVE.
   Weakness type (CWE)	added	—	CWE-476
   Reference	added	—	https://github.com/openssl/openssl/commit/37882aa2e0256e1072442a8f62f7db45b995c45b
   Reference	added	—	https://github.com/openssl/openssl/commit/a17cc8d612ecff6d94a9b7ca8b5283ddf5ff570e
   Reference	added	—	https://github.com/openssl/openssl/commit/a1f348ccb328c3afbd4ba6883f9b7c813c043259
   Reference	added	—	https://github.com/openssl/openssl/commit/a7af46a92d0ce19a90e669ef56d2576a07924226
   Reference	added	—	https://github.com/openssl/openssl/commit/cdacfff557389abfa9e4615abded2ec984517d6c
   Reference	added	—	https://openssl-library.org/news/secadv/20260825.txt

   Source identifier: openssl-security@openssl.org