# CVE-2026-78426: Logout bypass via alternate JWT spelling

> Attackers can bypass logout mechanisms in NeuVector by using noncanonical JWT encodings, maintaining access with revoked tokens until expiration.

- **Severity:** Low 2.0 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Sep 2026
- **Updated:** 28 Sep 2026
- **Also known as:** GHSA-wcx5-mq6c-c54j

## What is CVE-2026-78426?

CVE-2026-78426 is a low-severity authentication bypass vulnerability in SUSE neuvector, published on 17 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

The NeuVector JWT verifier accepts noncanonical Base64URL encodings of the same RSA signature field. An attacker holding a valid JWT that has not expired, but was logged out of NeuVector, can continue using the non-expired token with equivalent spelling of the RSA signature field until the token validity expires.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-78426?


## How do I fix CVE-2026-78426?

No fix has been published for CVE-2026-78426 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-78426 being exploited?

There is no known exploitation of CVE-2026-78426 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-78426 and fix it if it is affected.

What it is: CVE-2026-78426 is a low-severity authentication bypass vulnerability in SUSE neuvector, published on 17 Sep 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-78426 in the wild and no public exploit code.

Affected product: SUSE neuvector. 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-2026-78426/ (Markdown: https://insights.sbomify.com/CVE-2026-78426/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-78426
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-78426
- OSV: https://osv.dev/vulnerability/CVE-2026-78426

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-78426/
Summaries are generated and may contain mistakes; the official description above is the record.