# CVE-2026-59847: Libssh: libssh: integrity downgrade via openssl aes-gcm tag verification

> An in-path attacker can modify SSH traffic without detection due to flawed AES-GCM integrity checks in the OpenSSL backend of libssh.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jul 2026
- **Updated:** 1 Sep 2026
- **Also known as:** AZL-93246, BELL-CVE-2026-59847, CLSA-2026-1785837599, DEBIAN-CVE-2026-59847, ECHO-c402-a16c-cfd9, GHSA-mq2j-7vq4-77m8, MINI-g3rj-8m59-2gh6, UBUNTU-CVE-2026-59847

## What is CVE-2026-59847?

CVE-2026-59847 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 21 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.

Weakness: CWE-1310 (Missing Ability to Patch ROM Code), CWE-253 (Incorrect Check of Function Return Value)

## Which versions are affected by CVE-2026-59847?

It affects 3 products.


Products: Libssh Libssh, Redhat Enterprise Linux, Redhat Hardened Images.

## How do I fix CVE-2026-59847?

Apply the vendor's patch.

## Is CVE-2026-59847 being exploited?

There is no known exploitation of CVE-2026-59847 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2026-59851](https://insights.sbomify.com/CVE-2026-59851/): Libssh: libssh: authentication bypass via missing gssapi principal check (high 8.8)
- [CVE-2025-5987](https://insights.sbomify.com/CVE-2025-5987/): Libssh: invalid return code for chacha20 poly1305 with openssl backend (high 8.1)
- [CVE-2025-14821](https://insights.sbomify.com/CVE-2025-14821/): Libssh: libssh: insecure default configuration leads to local man-in-the-middle attacks on windows (high 7.8)
- [CVE-2012-4560](https://insights.sbomify.com/CVE-2012-4560/): Memory corruption in n/a (high 7.5)
- [CVE-2012-4562](https://insights.sbomify.com/CVE-2012-4562/): Integer overflow in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59847 and fix it if it is affected.

What it is: CVE-2026-59847 is a medium-severity vulnerability in Redhat Enterprise Linux, published on 21 Jul 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-2026-59847 in the wild and no public exploit code.

Affected product: Redhat Enterprise Linux. 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-2026-59847/ (Markdown: https://insights.sbomify.com/CVE-2026-59847/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59847
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59847
- OSV: https://osv.dev/vulnerability/CVE-2026-59847

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59847/
Summaries are generated and may contain mistakes; the official description above is the record.