# CVE-2026-75806: Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes DoS


- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 29 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** ALPINE-CVE-2026-75806, AZL-105354, AZL-105441, AZL-105486, AZL-105507, AZL-105597, AZL-105609, AZL-105714, AZL-105849, AZL-105897, BELL-CVE-2026-75806, CLEANSTART-2026-KP41215, DEBIAN-CVE-2026-75806, ECHO-c4dc-a1f8-f0ae, GHSA-4h8f-fwpc-hwwf, MINI-46c8-h957-fp9x, UBUNTU-CVE-2026-75806

## What is CVE-2026-75806?

CVE-2026-75806 is a medium-severity vulnerability in Openssl Openssl, published on 29 Sep 2026. 

### Official description

Issue summary: An established DTLS 1.2 association using an AEAD cipher suite
can be terminated by a single unauthenticated datagram whose encrypted
fragment is shorter than the mandatory explicit IV and authentication tag
overhead.

Impact summary: An attacker who can send a datagram that is routed to an
existing DTLS 1.2 association can tear that association down without knowing
any key material. This is a Denial of Service limited to the targeted
association. There is no memory safety or confidentiality impact.

CWE: CWE-1284: Improper Validation of Specified Quantity in Input

Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher
suite carries an explicit IV followed by the ciphertext and an authentication
tag. When decrypting such a record the record layer passed the record length to
the cipher implementation before checking that the record was long enough to
contain the explicit IV and the tag. For a record shorter than that overhead the
cipher implementation rejected the impossible length, and the record layer
treated this as an internal failure and raised a fatal internal_error alert
instead of treating the record as one that failed authentication.

In TLS 1.2 the same record causes a fatal internal_error alert instead of the
expected bad_record_mac alert. Since any undecryptable record already
terminates a TLS connection, this is a protocol conformance issue rather than
a security issue in TLS.

The fix validates the record length against the explicit IV and tag length
before any AEAD processing, so that TLS reports bad_record_mac and DTLS
silently discards the record.

FIPS impact: no
The affected code is outside the FIPS module boundary.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-75806?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2026-75806?

Upgrade to a fixed version.

## Is CVE-2026-75806 being exploited?

There is no known exploitation of CVE-2026-75806 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-2026-75806 and fix it if it is affected.

What it is: CVE-2026-75806 is a medium-severity vulnerability in Openssl Openssl, published on 29 Sep 2026. 
Exploitation: There is no known exploitation of CVE-2026-75806 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-2026-75806/ (Markdown: https://insights.sbomify.com/CVE-2026-75806/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75806
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75806
- OSV: https://osv.dev/vulnerability/CVE-2026-75806

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75806/
Summaries are generated and may contain mistakes; the official description above is the record.