CVE-2026-88915CWE-862broken-access-control

CVE-2026-88915

published September 10, 2026

CVSS
7.1
EPSS
0%
Percentile
27.5
In the wild
Unconfirmed
What it is

Affected versions of MISP do not consistently enforce the acting user's authorization when instantiating event templates.

For templates using distribution = 4, the template can specify a sharing_group_id. The instantiation path passed that value into event creation without verifying that the user instantiating the template was actually permitted to use the selected sharing group. The commit notes that Event::_add() only performed its own sharing-group authorization in another code path, leaving template instantiation able to write the identifier directly.

The same instantiation path also attached template-specified tags without checking the user's normal tagging permissions. In addition, it hardcoded local => 0, meaning tags marked local_only could be attached globally and consequently propagate through synchronization or export, contrary to their intended restriction.

The fix adds explicit SharingGroup::canUse() authorization for the acting user, applies the same tag-modification checks used by normal event tagging, and ensures local_only tags are attached locally.

Version affected: ≤2.5.45

The record
Technical detail
CVSS
7.1 · NONE
CVSS v4.0
7.1 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00351 · 27.5th percentile
Weakness
CWE-862 · Missing Authorization
Published
2026-09-10T18:17Z
References (1)
EPSS history
Timeline
  • 12 SEP 03:22Z
    EPSS moved — → 0%
    epss
  • 10 SEP 13:04Z
    MISP Event Template Instantiation Bypasses Sharing Group and Tagging Authorization
    cvelistv5