# CVE-2026-48058: nebula-mesh: Session and OIDC state cookies lack the Secure attribute

> Attackers can steal session cookies via plaintext requests because the Secure attribute is missing, potentially leading to account takeover.

- **Severity:** Medium 4.6 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Jul 2026
- **Updated:** 28 Jul 2026
- **Also known as:** GHSA-rqfj-vv8r-xhqc, GO-2026-5635

## What is CVE-2026-48058?

CVE-2026-48058 is a medium-severity vulnerability in juev nebula-mesh, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

nebula-mesh is a self-hosted control plane for Slack Nebula mesh virtual private network. Prior to version 0.3.2, internal/web/session.go and internal/web/oidc.go set HttpOnly and SameSite=Lax on every cookie but never Secure. A single plaintext request to the origin (operator on a LAN, mistyped URL, HTTP→HTTPS not strictly enforced, reverse proxy misconfiguration) discloses the session. This issue has been patched in version 0.3.2.

Weakness: CWE-614 (Sensitive Cookie in HTTPS Session Without 'Secure' Attribute)

## Which versions are affected by CVE-2026-48058?

3 open source packages ship an affected version, including github.com/juev/nebula-mesh.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/juev/nebula-mesh` | Go | All versions | 0.3.2 |
| `github.com/juev/nebula-mesh` | Go | All versions | 0.3.2 |
| `github.com/juev/nebula-mesh` | Go | All versions | 0.3.2 |

## How do I fix CVE-2026-48058?

Upgrade github.com/juev/nebula-mesh to 0.3.2 or later.

## Is CVE-2026-48058 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48058 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48058 and fix it if it is affected.

What it is: CVE-2026-48058 is a medium-severity vulnerability in juev nebula-mesh, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48058 exists.

Affected packages and fixed versions:
- github.com/juev/nebula-mesh (Go): affected all versions; fixed in 0.3.2
- github.com/juev/nebula-mesh (Go): affected all versions; fixed in 0.3.2
- github.com/juev/nebula-mesh (Go): affected all versions; fixed in 0.3.2

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-2026-48058/ (Markdown: https://insights.sbomify.com/CVE-2026-48058/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48058
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48058
- OSV: https://osv.dev/vulnerability/CVE-2026-48058

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48058/
Summaries are generated and may contain mistakes; the official description above is the record.