How severe is CVE-2026-40080?

CVE-2026-40080 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-40080 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40080?

CVE-2026-40080 affects Cacti. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40080?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-40080 have an EU (EUVD) identifier?

Yes. CVE-2026-40080 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39585.

When was CVE-2026-40080 published?

CVE-2026-40080 was published on 2026-06-25 and last updated on 2026-06-29.

CVE-2026-40080

CVE-2026-40080 is a medium-severity vulnerability in Cacti with a CVSS 3.x base score of 6.1. 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-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39585
Weakness: CWE-601
Affected product: Cacti
Published: 2026-06-25
Last modified: 2026-06-29

Description

Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior are vulnerable to Open Redirect through a substring check rather than a host check at str_contains($referer, CACTI_PATH_URL). When the user's login_opts == '1' (redirect to referer after login), the function used $_SERVER['HTTP_REFERER'] directly. An attacker could craft a referer such as https://evil.com/cacti/. Where CACTI_PATH_URL is /cacti/, the substring matches and the user is redirected to evil.com after login. The pre-existing validate_redirect_url() helper at lib/html_utility.php performed proper validation but was not invoked from auth_login_redirect(). This issue has been fixed in version 1.2.31.

Frequently asked questions

What is CVE-2026-40080?: Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior are vulnerable to Open Redirect through a substring check rather than a host check at str_contains($referer, CACTI_PATH_URL). When the user's login_opts == '1' (redirect to referer after login), the function used $_SERVER['HTTP_REFERER'] directly. An attacker could craft a referer such as https://evil.com/cacti/. Where CACTI_PATH_URL is /cacti/, the substring matches and the user is redirected to evil.com after login. The pre-existing validate_redirect_url() helper at lib/html_utility.php performed proper validation but was not invoked from auth_login_redirect(). This issue has been fixed in version 1.2.31.
How severe is CVE-2026-40080?: CVE-2026-40080 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-40080 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40080?: CVE-2026-40080 affects Cacti. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40080?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-40080 have an EU (EUVD) identifier?: Yes. CVE-2026-40080 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39585.
When was CVE-2026-40080 published?: CVE-2026-40080 was published on 2026-06-25 and last updated on 2026-06-29.

References

Affected products (1)

cpe:2.3:a:cacti:cacti:*:*:*:*:*:*:*:*

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