# CVE-2026-63076: Invalid Pointer Dereference in CMP Server via Crafted protectionAlg

> Remote attackers can crash CMP servers or clients by sending crafted messages with invalid protection algorithm parameters, causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Aug 2026
- **Updated:** 25 Aug 2026
- **Also known as:** ALPINE-CVE-2026-63076, AZL-97674, AZL-97887, AZL-97941, BELL-CVE-2026-63076, CLEANSTART-2026-MH33423, DEBIAN-CVE-2026-63076, ECHO-b5fe-8a22-4e2a, GHSA-r3hf-pf7x-wgqg, MINI-75v6-2r53-m3x8, MINI-7vw8-2728-hq68, ROOT-OS-ALPINE-317-CVE-2026-63076, ROOT-OS-DEBIAN-11-CVE-2026-63076, UBUNTU-CVE-2026-63076

## What is CVE-2026-63076?

CVE-2026-63076 is a high-severity vulnerability in Openssl Openssl, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-63076?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2026-63076?

Apply the vendor's patch.

## Is CVE-2026-63076 being exploited?

There is no known exploitation of CVE-2026-63076 in the wild and no public exploit code.

## Other vulnerabilities in Openssl Openssl

- [CVE-2009-3245](https://insights.sbomify.com/CVE-2009-3245/): Null dereference in n/a (critical 10.0)
- [CVE-2006-3738](https://insights.sbomify.com/CVE-2006-3738/): Memory corruption in n/a (critical 10.0)
- [CVE-2026-63073](https://insights.sbomify.com/CVE-2026-63073/): Untrusted Sender DN Used as Format String in CMP Response Validation (critical 9.8)
- [CVE-2016-6309](https://insights.sbomify.com/CVE-2016-6309/): Use after free in n/a (critical 9.8)
- [CVE-2016-0799](https://insights.sbomify.com/CVE-2016-0799/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63076 and fix it if it is affected.

What it is: CVE-2026-63076 is a high-severity vulnerability in Openssl Openssl, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-63076 in the wild and no public exploit code.

Affected product: Openssl Openssl. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63076/ (Markdown: https://insights.sbomify.com/CVE-2026-63076/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63076
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63076
- OSV: https://osv.dev/vulnerability/CVE-2026-63076

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63076/
Summaries are generated and may contain mistakes; the official description above is the record.