CVE-2026-34828 listmonk: Active sessions remain valid after password reset and password change
Attackers with stolen session cookies retain access after password changes, bypassing session invalidation in listmonk.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34828?
CVE-2026-34828 is a high-severity vulnerability in knadh listmonk, published on 2 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
listmonk is a standalone, self-hosted, newsletter and mailing list manager. From version 4.1.0 to before version 6.1.0, a session management vulnerability allows previously issued authenticated sessions to remain valid after sensitive account security changes, specifically password reset and password change. As a result, an attacker who has already obtained a valid session cookie can retain access to the account even after the victim changes or resets their password. This weakens account recovery and session security guarantees. This issue has been patched in version 6.1.0.
Weakness: CWE-613
Which versions are affected by CVE-2026-34828?
3 open source packages ship an affected version, including github.com/knadh/listmonk. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/knadh/listmonk Go | From 1.1.1-0.20241028090858-319053dd7a90 | 1.1.1-0.20260329113754-1b5e8d38c778 |
github.com/knadh/listmonk Go | From 1.1.1-0.20241028090858-319053dd7a90 | 1.1.1-0.20260329113754-1b5e8d38c778 |
github.com/knadh/listmonk Go | From 1.1.1-0.20241028090858-319053dd7a90 | 1.1.1-0.20260329113754-1b5e8d38c778 |
Products include Nadh Listmonk.
How do I fix CVE-2026-34828?
Upgrade github.com/knadh/listmonk to 1.1.1-0.20260329113754-1b5e8d38c778 or later.
Is CVE-2026-34828 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34828 exists.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in knadh listmonk
- CVE-2025-49136 listmonk's Sprig template Injection vulnerability leads to reading of Environment Variable for low privilege user
- CVE-2025-58430 listmonk Vulnerable to CSRF to XSS Chain That Can Lead to Admin Account Takeover
- CVE-2025-46011 SQL injection in n/a
- CVE-2026-34584 listmonk: Broken Access Control in CSV Import (Unauthorized List Assignment)
- CVE-2026-21483 listmonk Vulnerable to Stored XSS Leading to Admin Account Takeover
Sources
Also known as GHSA-h5j9-cvrw-v5qh, GO-2026-5414.