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CVE-2026-54395

MEDIUMCVSS 5.3/10EPSS 0.26%

Last modified

CVE-2026-54395 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. MISP contains a reflected cross-site scripting vulnerability in the UiBeta event index view. The urlparams value is inserted into an inline JavaScript handler using HTML escaping inside a single-quoted JavaScript string. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

MISP contains a reflected cross-site scripting vulnerability in the UiBeta event index view. The urlparams value is inserted into an inline JavaScript handler using HTML escaping inside a single-quoted JavaScript string. Because browsers HTML-decode attribute values before JavaScript parsing, a crafted searcheventinfo value can restore encoded quote characters and break out of the JavaScript string. An attacker could craft a malicious URL that, when opened by a victim using the UiBeta event index, executes arbitrary JavaScript in the victim’s browser in the context of the MISP instance. The issue is fixed by encoding the value as a JavaScript string literal with json_encode() before applying HTML escaping at the attribute layer.

Metrics

CVSS 4.0
5.3/10

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/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:X

EPSS Probability
0.26%

16.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-54395?
MISP contains a reflected cross-site scripting vulnerability in the UiBeta event index view. The urlparams value is inserted into an inline JavaScript handler using HTML escaping inside a single-quoted JavaScript string. Because browsers HTML-decode attribute values before JavaScript parsing, a crafted searcheventinfo value can restore encoded quote characters and break out of the JavaScript string. An attacker could craft a malicious URL that, when opened by a victim using the UiBeta event index, executes arbitrary JavaScript in the victim’s browser in the context of the MISP instance. The issue is fixed by encoding the value as a JavaScript string literal with json_encode() before applying HTML escaping at the attribute layer.
How severe is CVE-2026-54395?
CVE-2026-54395 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.
How do I fix CVE-2026-54395?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-54395?

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Source: NVD / NIST