HighCVE-2026-116469

MISP Guard Case-Sensitive Policy Bypass Allows Unauthorized Feed Data Forwarding (CVE-2026-116469)

Published 26.10.2026Last modified 27.10.2026Sources: EUVD, CVE.org

What is affected, what to do

The available sources name no fixed version. Check the vendor guidance in the references below.

Affected: Misp-guard lte *..1.3

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Metrics

7.1

Priority

XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

Source: Vendor (CNA), CVSS v4

7.1

CVSS v4

Severity High on the scale from 0 to 10.

Source: EUVD, CVE.org

0.4 %

EPSS score

Low — model estimates < 1% exploitation likelihood.

Source: FIRST EPSS, percentile 30.4

Show all metrics

Severity: High
Priority (0–325) The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first? Read in glossary: 72.88 Methodology
Exploit maturity An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack. Read in glossary: no public PoC known
XIEM Effective CVSS XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command. Read in glossary: 7.1 Methodology
CVSS v4 CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions. Read in glossary: 7.1
EPSS score The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“. Read in glossary: 0.4 %; Low — model estimates < 1% exploitation likelihood.
EPSS percentile The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking. Read in glossary: 30.4; Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching. Read in glossary: —
Published: 26.10.2026
CISA assessment (SSVC): Exploitation: none known · not automatable · Technical impact: partial; Source: CISA Vulnrichment, as of 26 October 2026
CWE CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect. Read in glossary: CWE-178, CWE-20

Detection rules

No NEOSEC detection rule is available for this vulnerability yet.

Classification under NIS2 and CRA

Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

NIS2 NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management. Read in glossary: High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates. Read in glossary: From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001 ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security. Read in glossary: Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

Description

MISP Guard, a proxy-based security filter for MISP feed distribution, contains a case-sensitivity flaw in multiple policy enforcement checks. The functions check_required_taxonomy_exists, check_required_taxonomy_tags_allowed, check_blocked_attribute_categories, and check_blocked_analyst_data_sharing_groups_uuids performed case-sensitive string comparisons when matching event tags, attribute categories, and sharing-group UUIDs against configured allow/block lists. An attacker with the ability to create or modify events in a MISP instance (or a connected instance that pushes events through the guard) could craft events using different letter case in taxonomy tag names, attribute categories, or sharing-group UUIDs to bypass the configured security policies. For example, if the policy requires the 'tlp' taxonomy with only 'tlp:clear' allowed, an event tagged 'TLP:AMBER' would not be recognized as belonging to the 'tlp' taxonomy and would therefore not be checked against the allowed-tags list, resulting in the event being forwarded to feed consumers. Similarly, a blocked attribute category such as 'Person' would not match a configured block entry of 'person', allowing the attribute to pass through the filter. The security impact is unauthorized disclosure of threat-intelligence data that the operator intended to restrict. Events carrying non-allowed TLP (Traffic Light Protocol) markings, blocked attribute categories, or blocked sharing-group associations are forwarded to downstream feed consumers in violation of the configured distribution policy. This undermines the confidentiality controls that MISP Guard is designed to enforce. The vulnerability is trivially exploitable: the attacker only needs to alter the letter case of a tag, category, or UUID string. No authentication beyond normal MISP event-creation privileges is required, and no user interaction is needed.

Source: ENISA EUVD, cvelistv5, NVD (NIST), CVE.org (MITRE)

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

Affected products
		Affected versions	Fixed in
MISP	misp-guard	`≤ 1.3`	—

Vendors and products

MISP Misp-guard

Weakness classes (CWE)

CWE-178Improper Handling of Case Sensitivity
Base
The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results.
Entry at MITRE CWE-178
CWE-20Improper Input Validation
Class
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Entry at MITRE CWE-20

References & sources

github.comSecurity patcheuvd, Patch

Changes to this CVE

Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

27.10.2026Record modifiedCIRCL

Description added or changed

Show 2 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	changed	MISP Guard, a proxy-based security filter for MISP (Malware Information Sharing Platform) feed distribution, contains a case-sensitivity flaw in multiple policy enforcement checks. The functions check_required_taxonomy_exists, check_required_taxonomy_tags_allowed, check_blocked_attribute_categories, and check_blocked_analyst_data_sharing_groups_uuids performed case-sensitive string comparisons when matching event tags, attribute categories, and sharing-group UUIDs against configured allow/block lists. An attacker with the ability to create or modify events in a MISP instance (or a connected instance that pushes events through the guard) could craft events using different letter case in taxonomy tag names, attribute categories, or sharing-group UUIDs to bypass the configured security policies. For example, if the policy requires the 'tlp' taxonomy with only 'tlp:clear' allowed, an event tagged 'TLP:AMBER' would not be recognized as belonging to the 'tlp' taxonomy and would therefore not be checked against the allowed-tags list, resulting in the event being forwarded to feed consumers. Similarly, a blocked attribute category such as 'Person' would not match a configured block entry of 'person', allowing the attribute to pass through the filter. The security impact is unauthorized disclosure of threat-intelligence data that the operator intended to restrict. Events carrying non-allowed TLP (Traffic Light Protocol) markings, blocked attribute categories, or blocked sharing-group associations are forwarded to downstream feed consumers in violation of the configured distribution policy. This undermines the confidentiality controls that MISP Guard is designed to enforce. The vulnerability is trivially exploitable: the attacker only needs to alter the letter case of a tag, category, or UUID string. No authentication beyond normal MISP event-creation privileges is required, and no user interaction is needed.	MISP Guard, a proxy-based security filter for MISP feed distribution, contains a case-sensitivity flaw in multiple policy enforcement checks. The functions check_required_taxonomy_exists, check_required_taxonomy_tags_allowed, check_blocked_attribute_categories, and check_blocked_analyst_data_sharing_groups_uuids performed case-sensitive string comparisons when matching event tags, attribute categories, and sharing-group UUIDs against configured allow/block lists. An attacker with the ability to create or modify events in a MISP instance (or a connected instance that pushes events through the guard) could craft events using different letter case in taxonomy tag names, attribute categories, or sharing-group UUIDs to bypass the configured security policies. For example, if the policy requires the 'tlp' taxonomy with only 'tlp:clear' allowed, an event tagged 'TLP:AMBER' would not be recognized as belonging to the 'tlp' taxonomy and would therefore not be checked against the allowed-tags list, resulting in the event being forwarded to feed consumers. Similarly, a blocked attribute category such as 'Person' would not match a configured block entry of 'person', allowing the attribute to pass through the filter. The security impact is unauthorized disclosure of threat-intelligence data that the operator intended to restrict. Events carrying non-allowed TLP (Traffic Light Protocol) markings, blocked attribute categories, or blocked sharing-group associations are forwarded to downstream feed consumers in violation of the configured distribution policy. This undermines the confidentiality controls that MISP Guard is designed to enforce. The vulnerability is trivially exploitable: the attacker only needs to alter the letter case of a tag, category, or UUID string. No authentication beyond normal MISP event-creation privileges is required, and no user interaction is needed.
Affected versions (publisher)	added	—	Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/116xxx/CVE-2026-116469.json">CVE-2026-116469</a>

Source identifier: 5a6e4751-2f3f-4070-9419-94fb35b644e8

26.10.2026Record modifiedCISA ADP

CISA assessment (SSVC): exploitation: none known, automatable: no

Show the original change

Individual changes of this event as published by NVD
Type	Action	Before	After
SSVC assessment	added	—	{"id":"CVE-2026-116469","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-26T13:32:47.760705Z"}

Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

26.10.2026ReceivedCIRCL

CVSS V4.0: AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

CISA assessment (SSVC): exploitation: none known, automatable: yes

Weakness type: CWE-20, CWE-178

Description added or changed

New references:

https://github.com/MISP/misp-guard/commit/9868b1d93fc9cc40cc7c69ca11c86afd825bbc1c

Show 7 original changes

Individual changes of this event as published by NVD
Type	Action	Before	After
Description	added	—	MISP Guard, a proxy-based security filter for MISP (Malware Information Sharing Platform) feed distribution, contains a case-sensitivity flaw in multiple policy enforcement checks. The functions check_required_taxonomy_exists, check_required_taxonomy_tags_allowed, check_blocked_attribute_categories, and check_blocked_analyst_data_sharing_groups_uuids performed case-sensitive string comparisons when matching event tags, attribute categories, and sharing-group UUIDs against configured allow/block lists. An attacker with the ability to create or modify events in a MISP instance (or a connected instance that pushes events through the guard) could craft events using different letter case in taxonomy tag names, attribute categories, or sharing-group UUIDs to bypass the configured security policies. For example, if the policy requires the 'tlp' taxonomy with only 'tlp:clear' allowed, an event tagged 'TLP:AMBER' would not be recognized as belonging to the 'tlp' taxonomy and would therefore not be checked against the allowed-tags list, resulting in the event being forwarded to feed consumers. Similarly, a blocked attribute category such as 'Person' would not match a configured block entry of 'person', allowing the attribute to pass through the filter. The security impact is unauthorized disclosure of threat-intelligence data that the operator intended to restrict. Events carrying non-allowed TLP (Traffic Light Protocol) markings, blocked attribute categories, or blocked sharing-group associations are forwarded to downstream feed consumers in violation of the configured distribution policy. This undermines the confidentiality controls that MISP Guard is designed to enforce. The vulnerability is trivially exploitable: the attacker only needs to alter the letter case of a tag, category, or UUID string. No authentication beyond normal MISP event-creation privileges is required, and no user interaction is needed.
CVSS	added	—	AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/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 type (CWE)	added	—	CWE-20
Weakness type (CWE)	added	—	CWE-178
Affected versions (publisher)	added	—	New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/116xxx/CVE-2026-116469.json">CVE-2026-116469</a>
Reference	added	—	https://github.com/MISP/misp-guard/commit/9868b1d93fc9cc40cc7c69ca11c86afd825bbc1c
SSVC assessment	added	—	{"role":"Supplier","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-26T10:33:59Z"}

Source identifier: 5a6e4751-2f3f-4070-9419-94fb35b644e8

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