# CVE-2026-28387: Potential Use-after-free in DANE Client Code

> A use-after-free in OpenSSL's DANE client code allows arbitrary code execution or crashes when specific TLSA record combinations are used.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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:** 7 Apr 2026
- **Updated:** 15 Oct 2026
- **Also known as:** ALPINE-CVE-2026-28387, AZL-81947, AZL-82103, BELL-CVE-2026-28387, CLSA-2026-1777455447, CLSA-2026-1777542789, CLSA-2026-1777567502, DEBIAN-CVE-2026-28387, ECHO-6fc6-4872-7ea8, GHSA-h2cc-wx97-xp8v, JLSEC-2026-272, MINI-g2v9-6998-mmpm, MINI-j8h3-pj3q-rjj2, MINI-rfjw-6mc7-895q, ROOT-OS-ALPINE-315-CVE-2026-28387, ROOT-OS-ALPINE-317-CVE-2026-28387, UBUNTU-CVE-2026-28387

## What is CVE-2026-28387?

CVE-2026-28387 is a high-severity use after free vulnerability in Openssl Openssl, published on 7 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: An uncommon configuration of clients performing DANE TLSA-based
server authentication, when paired with uncommon server DANE TLSA records, may
result in a use-after-free and/or double-free on the client side.

Impact summary: A use after free can have a range of potential consequences
such as the corruption of valid data, crashes or execution of arbitrary code.

However, the issue only affects clients that make use of TLSA records with both
the PKIX-TA(0/PKIX-EE(1) certificate usages and the DANE-TA(2) certificate
usage.

By far the most common deployment of DANE is in SMTP MTAs for which RFC7672
recommends that clients treat as 'unusable' any TLSA records that have the PKIX
certificate usages.  These SMTP (or other similar) clients are not vulnerable
to this issue.  Conversely, any clients that support only the PKIX usages, and
ignore the DANE-TA(2) usage are also not vulnerable.

The client would also need to be communicating with a server that publishes a
TLSA RRset with both types of TLSA records.

No FIPS modules are affected by this issue, the problem code is outside the
FIPS module boundary.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-28387?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2026-28387?

Apply the vendor's patch.

## Is CVE-2026-28387 being exploited?

There is no known exploitation of CVE-2026-28387 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-2026-28387 and fix it if it is affected.

What it is: CVE-2026-28387 is a high-severity use after free vulnerability in Openssl Openssl, published on 7 Apr 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-2026-28387 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-2026-28387/ (Markdown: https://insights.sbomify.com/CVE-2026-28387/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-28387
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-28387
- OSV: https://osv.dev/vulnerability/CVE-2026-28387

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-28387/
Summaries are generated and may contain mistakes; the official description above is the record.