CVE-2026-8699

CVE-2026-8699 is a high-severity vulnerability with a CVSS 4.0 base score of 7.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Description

A stored Cross-Site Scripting (XSS) vulnerability has been identified in the web-based management interface of Archer C5 v6.8 routers, due to insufficient server-side validation and lack of proper output encoding of user-controlled input in a certain field.  An attacker with administrative privileges can inject crafted HTML or JS payloads into the affected field. The payload is stored and later executed when the affected page is rendered in an administrator's browser.Successful exploitation allows execution of arbitrary JavaScript in an admin's browser, potentially leading to session hijacking and unauthorized access to router configuration, possibly resulting in exposure of sensitive data and modification of device settings. The vulnerability affects ISP-managed firmware variants of the product. Remediation is coordinated through service providers.

Frequently asked questions

What is CVE-2026-8699?
A stored Cross-Site Scripting (XSS) vulnerability has been identified in the web-based management interface of Archer C5 v6.8 routers, due to insufficient server-side validation and lack of proper output encoding of user-controlled input in a certain field.  An attacker with administrative privileges can inject crafted HTML or JS payloads into the affected field. The payload is stored and later executed when the affected page is rendered in an administrator's browser.Successful exploitation allows execution of arbitrary JavaScript in an admin's browser, potentially leading to session hijacking and unauthorized access to router configuration, possibly resulting in exposure of sensitive data and modification of device settings. The vulnerability affects ISP-managed firmware variants of the product. Remediation is coordinated through service providers.
How severe is CVE-2026-8699?
CVE-2026-8699 has a CVSS 4.0 base score of 7.0, rated high severity.
Is CVE-2026-8699 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-8699?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-8699 published?
CVE-2026-8699 was published on 2026-07-02.

References

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