# CVE-2026-40082: Cacti: Session Fixation via missing session_regenerate_id() after login

> Attackers can hijack user sessions in Cacti due to missing session ID regeneration after login, allowing unauthorized access to victim accounts.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 25 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-40082, GHSA-273r-qr93-wgcp, UBUNTU-CVE-2026-40082

## What is CVE-2026-40082?

CVE-2026-40082 is a medium-severity authentication bypass vulnerability in Cacti Cacti, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior have missing session_regenerate_id() after login, leading to Session Fixation. session_regenerate_id() is NOT called after successful login. The login flow at auth_login.php:203-207 directly sets $_SESSION[SESS_USER_ID] without rotating the session ID. The session cookie configuration is otherwise good (httponly=true, samesite=Strict, secure=true for HTTPS at include/global.php:513-537), but these do not prevent session fixation via same-site vectors. This issue has been fixed in version 1.2.31.

Weakness: CWE-384 (Session Fixation)

## Which versions are affected by CVE-2026-40082?

It affects 1 product.


Products: Cacti Cacti.

## How do I fix CVE-2026-40082?

Upgrade to a fixed version.

## Is CVE-2026-40082 being exploited?

There is no known exploitation of CVE-2026-40082 in the wild and no public exploit code.

## Other vulnerabilities in Cacti Cacti

- [CVE-2022-46169](https://insights.sbomify.com/CVE-2022-46169/): Cacti Command Injection (critical 9.8, exploited in the wild)
- [CVE-2026-39893](https://insights.sbomify.com/CVE-2026-39893/): Cacti: Pre-authentication SQL injection via rfilter RLIKE clause in graph_view.php (critical 9.8)
- [CVE-2026-39938](https://insights.sbomify.com/CVE-2026-39938/): Cacti: Unauthenticated RCE on Graph Image (critical 9.8)
- [CVE-2026-39955](https://insights.sbomify.com/CVE-2026-39955/): Cacti has Pre-Authentication SQL Injection via unanchored FILTER_VALIDATE_REGEXP in graph_view.php (critical 9.8)
- [CVE-2023-39361](https://insights.sbomify.com/CVE-2023-39361/): Unauthenticated SQL Injection in graph_view.php in Cacti (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40082 and fix it if it is affected.

What it is: CVE-2026-40082 is a medium-severity authentication bypass vulnerability in Cacti Cacti, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-40082 in the wild and no public exploit code.

Affected product: Cacti Cacti. 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-2026-40082/ (Markdown: https://insights.sbomify.com/CVE-2026-40082/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40082
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40082
- OSV: https://osv.dev/vulnerability/CVE-2026-40082

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40082/
Summaries are generated and may contain mistakes; the official description above is the record.