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CVE-2026-85533

MISP Sharing Group Authorization Bypass via Omitted Distribution Parameter

7.6 High

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
None

Exploit likelihood

0.37%Up 0.2 points since Sep 4, 2026
90%50%10%1%

What each source reports

CVE List Score used7.6

MISP Sharing Group Authorization Bypass via Omitted Distribution Parameter

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Record
CVE-2026-85533
CVSS 4.0
7.6 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-862
Updated
2026-11-02
EUVDEUVD-2026-709767.6

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Record
EUVD-2026-70976
CVSS 4.0
7.6 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-4pv3-xjc8-wfm87.6

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without...

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Record
GHSA-4pv3-xjc8-wfm8
CVSS 4.0
7.6 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/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
Weakness
CWE-862
Updated
2026-11-02
NVD7.6

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Record
CVE-2026-85533
CVSS 4.0
7.6 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/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
Weakness
CWE-862
Updated
2026-11-02
OSV7.6

MISP Sharing Group Authorization Bypass via Omitted Distribution Parameter

An authorization flaw in MISP allowed an authenticated user to submit a sharing_group_id without verifying that the user was authorized to use the referenced Sharing Group.

In several attribute and Galaxy Cluster creation and editing workflows, validation of the submitted Sharing Group was performed only when the request explicitly set the distribution field to 4 ("Sharing Group"). An attacker could therefore craft a request containing a sharing_group_id while omitting the distribution parameter, or otherwise avoiding the distribution == 4 condition, causing the Sharing Group authorization check to be skipped.

This could allow a user with permission to create or modify the affected MISP objects to associate data with a Sharing Group that they are not authorized to use. Depending on the affected object's existing distribution settings and subsequent processing, this could bypass intended information-sharing boundaries and result in unauthorized placement or distribution of data to members of another Sharing Group.

The issue affected attribute attachment and editing operations as well as Galaxy Cluster creation and editing. The fix ensures that authorization is performed whenever a non-empty sharing_group_id is submitted, independently of the distribution parameter. It also centralizes the authorization decision in SharingGroup::canUse() and explicitly rejects empty Sharing Group identifiers rather than allowing them to be interpreted as an unrestricted query.

Record
CVE-2026-85533
CVSS 4.0
7.6 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Weakness
CWE-862
Updated
2026-11-02

Affected products

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-85533 is a high vulnerability (CVSS 7.6) in Misp, published September 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 31st percentile. No source names a fixed version.

References

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