# CVE-2026-34582: Botan has a TLS 1.3 certificate authentication bypass


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 7 Apr 2026
- **Updated:** 15 Jul 2026
- **Also known as:** ALPINE-CVE-2026-34582, AZL-81942, DEBIAN-CVE-2026-34582, GHSA-pxcj-9ppx-g86g, UBUNTU-CVE-2026-34582, openSUSE-SU-2026:20528-1

## What is CVE-2026-34582?

CVE-2026-34582 is a high-severity vulnerability in randombit botan, published on 7 Apr 2026. 

### Official description

Botan is a C++ cryptography library. Prior to version 3.11.1, the TLS 1.3 implementation allowed ApplicationData records to be processed prior to the Finished message being received. A server which is attempting to enforce client authentication via certificates can by bypassed by a client which entirely omits Certificate, CertificateVerify, and the Finished message and instead sends application data records. This vulnerability is fixed in 3.11.1.

Weakness: CWE-166 (Improper Handling of Missing Special Element), CWE-841 (Improper Enforcement of Behavioral Workflow)

## Which versions are affected by CVE-2026-34582?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `Botan` | openSUSE:Leap 16.0 | All versions | 3.7.1-160000.3.1 |

Products: Botan Project Botan.

## How do I fix CVE-2026-34582?

Upgrade to a fixed version.

## Is CVE-2026-34582 being exploited?

There is no known exploitation of CVE-2026-34582 in the wild and no public exploit code.

## Other vulnerabilities in randombit botan

- [CVE-2021-24115](https://insights.sbomify.com/CVE-2021-24115/): Information disclosure in n/a (critical 9.8)
- [CVE-2018-9127](https://insights.sbomify.com/CVE-2018-9127/): Security feature bypass in n/a (critical 9.8)
- [CVE-2015-7826](https://insights.sbomify.com/CVE-2015-7826/): Security feature bypass in n/a (critical 9.8)
- [CVE-2016-6878](https://insights.sbomify.com/CVE-2016-6878/): Other in n/a (critical 9.8)
- [CVE-2016-9132](https://insights.sbomify.com/CVE-2016-9132/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34582 and fix it if it is affected.

What it is: CVE-2026-34582 is a high-severity vulnerability in randombit botan, published on 7 Apr 2026. 
Exploitation: There is no known exploitation of CVE-2026-34582 in the wild and no public exploit code.

Affected product: randombit botan. 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-2026-34582/ (Markdown: https://insights.sbomify.com/CVE-2026-34582/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34582
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34582
- OSV: https://osv.dev/vulnerability/CVE-2026-34582

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34582/
Summaries are generated and may contain mistakes; the official description above is the record.