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Fencer Intel
medium 6.1

CVE-2026-10856 json

Open redirect in MISP dashboard button widget URL handling

published 5mo ago modified 3mo ago also EUVD-2026-34262

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

A URL validation flaw in the MISP dashboard button widget allowed a crafted relative-looking URL to be accepted as a local path while being interpreted by browsers as an external URL. The validation rejected URLs containing an explicit scheme, host, or user component, but did not reject paths beginning with a slash followed by a backslash, such as /\example.com. Some browsers normalize backslashes in URLs as forward slashes, which can turn this into a scheme-relative external navigation target. In addition, the generated href concatenated the reconstructed URL with the original URL, increasing the possibility of unsafe or malformed link generation.

An attacker able to configure or influence a dashboard button URL could craft a button that appears to point inside the application but redirects users to an attacker-controlled site when clicked. This could be used for phishing, credential theft, or social engineering. The patch fixes the issue by rejecting empty paths and paths starting with /\, and by emitting only the reconstructed validated URL in the anchor href.

Patch / fix

  • misp-project misp 2.5.39

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5mo ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N/U:Green
CNA 4.0 5.1 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/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:Green
NVD 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

  • misp misp

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Intel 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.