CyberSecBulletin
CVE-2026-14452NVD status: Deferred

Checkmk: URL Redirection to Untrusted Site

Published Updated By the CyberSecBulletin desk

CVE-2026-14452 is a high-severity URL redirection to untrusted site vulnerability in Checkmk, with a CVSS 4.0 base score of 8.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 2.5.0p15, 2.4.0p38, 2.3.0p51 as the first without the flaw, so updating Checkmk to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.29% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Checkmk to 2.5.0p15 or 2.4.0p38 or 2.3.0p51, whichever matches your release line, or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
CheckmkCheckmk2.5.0 up to, but not including, 2.5.0p15; 2.4.0 up to, but not including, 2.4.0p38; 2.3.0 up to, but not including, 2.3.0p51; 2.2.02.5.0p15, 2.4.0p38, 2.3.0p51

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
NoneNo account or login is needed.
User interaction
ActiveA user must deliberately do something unusual, such as dismissing a warning.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
HighSerious loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
LowLimited loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (checkmk.com).

Official description

Improper validation of the reset_url parameter of the Setup in-page search in Checkmk <2.5.0p15, <2.4.0p38, <2.3.0p51 and 2.2.0 (EOL) allows an attacker to execute arbitrary script in the session of an authenticated user with Setup access, or to redirect that user to an arbitrary external site, by tricking the user into opening a crafted URL and clicking the Reset button or submitting an empty search.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: URL Redirection to Untrusted Site

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

How developers prevent this class of flaw

  • Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
  • When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to /login.asp and ID 2 could map to http://www.example.com/. Features such as the ESAPI AccessReferenceMap provide this capability.
  • Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application. Be sure that the nonce is not predictable (CWE-330).

More URL Redirection to Untrusted Site vulnerabilities (CWE-601)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).

References

Other references

Other vulnerabilities in Checkmk

All Checkmk vulnerabilities

Recent URL Redirection to Untrusted Site vulnerabilities

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