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Fencer Vulns
medium 6.1

CVE-2026-40080 json

Cacti: Open Redirect via HTTP_REFERER substring check in auth_login_redirect

published 2026-06-25 4 mo ago modified 2026-06-29 4 mo ago also EUVD-2026-39585

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

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.

Patch / fix

  • cacti cacti 1.2.31
  • cacti Debian 14 1.2.31+ds1-1

debian advisories DEBIAN-CVE-2026-40080

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-40080 updated cvss 6.1

cacti: open redirect via HTTP_REFERER substring check in auth_login_redirect

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
4 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected products

  • Cacti cacti

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.