CVE-2026-9136: A vulnerability was identified in the ShadowAttribute proposal creation workflow. The add action accepted user-controlled ShadowAttribute request data...

Description

A vulnerability was identified in the ShadowAttribute proposal creation workflow. The add action accepted user-controlled ShadowAttribute request data without removing the id field before saving the record. Because the underlying framework treats a supplied primary key as an instruction to update an existing record, an authenticated user able to submit shadow attribute proposals could provide the identifier of an existing ShadowAttribute and cause that record to be updated instead of creating a new proposal. This can result in unauthorized modification of existing shadow attributes, potentially affecting proposals associated with events the user should not be able to alter. Depending on deployment configuration and accessible API responses, the issue may also expose or move proposal data across event contexts. The vulnerability is caused by trusting a client-supplied primary key during object creation. The fix removes the id field from incoming ShadowAttribute data before processing, ensuring that the endpoint always creates a new proposal rather than updating an existing one. This has been fixed in MISP 2.5.38.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS 4.0

8.3/10

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

0.23%

13.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-639

Affected Software

Vendor	Product	Versions
Misp-Project	Misp	>= 2.5.0, < 2.5.38

References

https://github.com/MISP/MISP/commit/49911b1d4b6e4517d803e50e3d980aaa4d37c16dPatch

Timeline

Published: May 20, 2026
Last Modified: Jun 22, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-9136?

A vulnerability was identified in the ShadowAttribute proposal creation workflow. The add action accepted user-controlled ShadowAttribute request data without removing the id field before saving the record. Because the underlying framework treats a supplied primary key as an instruction to update an existing record, an authenticated user able to submit shadow attribute proposals could provide the identifier of an existing ShadowAttribute and cause that record to be updated instead of creating a new proposal. This can result in unauthorized modification of existing shadow attributes, potentially affecting proposals associated with events the user should not be able to alter. Depending on deployment configuration and accessible API responses, the issue may also expose or move proposal data across event contexts. The vulnerability is caused by trusting a client-supplied primary key during object creation. The fix removes the id field from incoming ShadowAttribute data before processing, ensuring that the endpoint always creates a new proposal rather than updating an existing one. This has been fixed in MISP 2.5.38.

How severe is CVE-2026-9136?

CVE-2026-9136 has a CVSS score of 8.3/10 (HIGH severity). The EPSS model estimates a 0.23% probability of exploitation in the next 30 days.

How do I fix CVE-2026-9136?

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.