# CVE-2026-34820: Endian Firewall stored XSS in IPsec remark parameter

Source: https://junglewise.ai/threats/cve-2026-34820-endian-firewall-stored-xss-in-ipsec-remark-parameter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-02. Updated: 2026-07-24  
License: CC BY 4.0 with a link back

CVE-2026-34820 · Severity: medium · CVSS 6.4 · Published 2026-04-02

Endian Firewall, a security appliance used to protect corporate networks, contains a vulnerability in its IPsec management interface. An authorized user can inject malicious code into the system's configuration notes. This code then runs in the browsers of other administrators who view the page, potentially allowing an attacker to hijack sessions or perform unauthorized administrative actions.

Technologies: [Endian Firewall Community](https://junglewise.ai/threats/technologies/firewall-community). Vendors: [Endian](https://junglewise.ai/threats/vendors/endian).

## Quick answers

**Is CVE-2026-34820 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34820 being exploited in the wild.

**How severe is CVE-2026-34820?** Medium severity, with a CVSS score of 6.4, published 2 April 2026.

**Which products and versions are affected?** Endian Endian Firewall <= 3.3.25.

**Is there a fix for CVE-2026-34820?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-34820 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-34820?** Check whether you run Endian Firewall Community. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A stored cross-site scripting (XSS) vulnerability exists in Endian Firewall version 3.3.25 and earlier. The flaw is located in the 'remark' parameter within the /manage/ipsec/ endpoint, which fails to properly neutralize user-supplied input before it is stored and rendered. An authenticated attacker with network access to the management interface can submit a malicious payload that will execute arbitrary JavaScript in the context of any user who subsequently views the IPsec management page. This can lead to session hijacking or unauthorized configuration changes. The vulnerability is tracked as CVE-2026-34820.

## Affected products

- Endian Endian Firewall <= 3.3.25

## Timeline

- 2026-04-02: disclosed
- 2026-04-02: advisory

## References

- [https://help.endian.com/hc/en-us/sections/360004371358-Community](https://help.endian.com/hc/en-us/sections/360004371358-Community)
- [https://www.vulncheck.com/advisories/endian-firewall-manage-ipsec-remark-stored-cross-site-scripting](https://www.vulncheck.com/advisories/endian-firewall-manage-ipsec-remark-stored-cross-site-scripting)

## Related threats

- [Endian Firewall stored XSS in remark parameter](https://junglewise.ai/threats/cve-2026-34823-endian-firewall-stored-xss-in-remark-parameter)
- [Endian Firewall stored XSS in certificate management interface](https://junglewise.ai/threats/cve-2026-34822-endian-firewall-stored-xss-in-certificate-management-interface)
- [Endian Firewall stored XSS in VPN user remark parameter](https://junglewise.ai/threats/cve-2026-34821-endian-firewall-stored-xss-in-vpn-user-remark-parameter)
- [Endian Firewall stored XSS in openvpnclient.cgi](https://junglewise.ai/threats/cve-2026-34819-endian-firewall-stored-xss-in-openvpnclient-cgi)
- [Endian Firewall stored XSS in dnsmasq local domains remark parameter](https://junglewise.ai/threats/cve-2026-34818-endian-firewall-stored-xss-in-dnsmasq-local-domains-remark)