# CVE-2026-42769: Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate

> A typo in OpenSSL's CMP root CA key update verification allows a Registration Authority to substitute the root CA trust anchor, escalating privileges to root CA level.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Jun 2026
- **Updated:** 10 Jun 2026
- **Also known as:** ALPINE-CVE-2026-42769, AZL-92840, BELL-CVE-2026-42769, CLSA-2026-1782386492, DEBIAN-CVE-2026-42769, GHSA-rpj2-p5pj-r33v, JLSEC-2026-1141, MINI-9pw9-7q9c-mmjj, UBUNTU-CVE-2026-42769

## What is CVE-2026-42769?

CVE-2026-42769 is a medium-severity authentication bypass vulnerability in Openssl Openssl, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Issue Summary: An error in the callback used to verify the certificate
provided in a Root CA key update Certificate Management Protocol (CMP)
message response rendered the certificate validation ineffectual, which
could lead to escalation of credentials from the Registration Authority (RA)
level to the root Certification Authority (root CA) level.

Impact Summary: The Registration Autority could replace the root CA
certificate for the CMP clients with an arbitrary root CA certificate.

One of the parts of the Certificate Management Protocol (CMP), specified in
RFC 9810, is Root Certification Authority (root CA) key Rollover,
which is sent by the server in a message with type 'id-it-rootCaKeyUpdate'.
As part of these messages, 'newWithOld' certificate, the new root CA
certificate signed with the old root CA key, is provided, and verifying its
signature is crucial for transferring the trust from the old CA key to the
new one.

The 'id-it-rootCaKeyUpdate' messages are expected to be processed with
OSSL_CMP_get1_rootCaKeyUpdate(), that is expected to verify the 'newWithOld'
certificate.  A typo in the certificate chain building code led to adding
an incorrect certificate ('newWithOld' instead of 'oldRoot') to the
certificate chain, rendering the certificate verification process ineffectual
(only the issuer name and the algorithm OIDs were verified by other parts
of the verification code).

An attacker who already has credentials that satisfy the CMP message
protection checks can generate a new key pair and use a crafted self-signed
certificate in its 'id-it-rootCaKeyUpdate' CMP messages which affected CMP
clients would accept as a new trust anchor.

Significant preconditions for the attack (having valid RA-level credentials)
are the reason the issue was assigned Low severity.

The FIPS modules are not affected by this issue, as the affected code is
outside the OpenSSL FIPS module boundary.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-42769?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2026-42769?

Apply the vendor's patch.

## Is CVE-2026-42769 being exploited?

There is no known exploitation of CVE-2026-42769 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-2026-42769 and fix it if it is affected.

What it is: CVE-2026-42769 is a medium-severity authentication bypass vulnerability in Openssl Openssl, published on 9 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42769 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-2026-42769/ (Markdown: https://insights.sbomify.com/CVE-2026-42769/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42769
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42769
- OSV: https://osv.dev/vulnerability/CVE-2026-42769

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42769/
Summaries are generated and may contain mistakes; the official description above is the record.