MISP contains an authorization bypass in the related events listing functionality. When a user requests the list of events correlated to a given event, the system retrieved related event metadata directly from the correlation table without re-validating the caller's access rights against each related event.
The correlation table stores a snapshot of the event's distribution level and sharing group at the time the correlation was created, and does not carry the published flag. As a result, events that the caller is not permitted to open—because they are unpublished, or because their distribution or sharing group has changed since the correlation was recorded—were still returned with their metadata (title, date, correlating value counts).
Preconditions:
- An authenticated user with access to at least one event in MISP.
- The existence of correlation entries linking that event to other events the user should not be able to view.
Impact:
- Unauthorized disclosure of event metadata (titles, dates, correlation counts) for events the user has no right to access.
- Potential reconnaissance of threat-intelligence event names and timelines across sharing groups.
Affected: MISP versions prior to the fix commit (2ffa97f05).
"}],"value":"MISP contains an authorization bypass in the related events listing functionality. When a user requests the list of events correlated to a given event, the system retrieved related event metadata directly from the correlation table without re-validating the caller's access rights against each related event.\n\nThe correlation table stores a snapshot of the event's distribution level and sharing group at the time the correlation was created, and does not carry the published flag. As a result, events that the caller is not permitted to open—because they are unpublished, or because their distribution or sharing group has changed since the correlation was recorded—were still returned with their metadata (title, date, correlating value counts).\n\nPreconditions:\n\n- An authenticated user with access to at least one event in MISP.\n\n- The existence of correlation entries linking that event to other events the user should not be able to view.\n\nImpact:\n\n- Unauthorized disclosure of event metadata (titles, dates, correlation counts) for events the user has no right to access.\n\n- Potential reconnaissance of threat-intelligence event names and timelines across sharing groups.\n\nAffected: MISP versions prior to the fix commit (2ffa97f05)."}],"impacts":[{"capecId":"CAPEC-126","descriptions":[{"lang":"en","value":"CAPEC-126 Leverage Trusted Relationship"}]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":5.3,"baseSeverity":"MEDIUM","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]},{"format":"SSVC","other":{"content":{"options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"Supplier","timestamp":"2026-10-02T15:59:27Z","version":"2.0.3"},"type":"SSVC"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-862","description":"CWE-862 Missing Authorization","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-285","description":"CWE-285 Improper Authorization","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-02T16:01:32.781Z","orgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","shortName":"CIRCL"},"references":[{"name":"Security patch","tags":["patch"],"url":"https://github.com/MISP/MISP/commit/2ffa97f05"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"The fix enforces proper per-event authorization on the related events query by applying the user's full access-control conditions (including published status, distribution level, and sharing group membership) to the event lookup, rather than relying solely on the stale distribution snapshot stored in the correlation table. This ensures that only events the caller is currently permitted to read are returned in the related events list.
"}],"value":"The fix enforces proper per-event authorization on the related events query by applying the user's full access-control conditions (including published status, distribution level, and sharing group membership) to the event lookup, rather than relying solely on the stale distribution snapshot stored in the correlation table. This ensures that only events the caller is currently permitted to read are returned in the related events list."}],"title":"MISP Information Disclosure via Related Events Listing Bypassing Per-Event Authorization","x_gcve":[{"extensions":{"bcp-05-x-01":{"ai_annotations":[{"ai_level":"generated","description":"Draft vulnerability metadata was generated from a git-format patch using an Ollama-hosted language model. Human validation is required before publication.","gna_source":1,"models":[{"gna_source":1,"identifier":"qwen3.8:27b","name":"qwen3.8:27b","source":"ollama"}],"review_status":"full","scope":"record","tags":["ai-computer-assisted:llm-generated","ai-computer-assisted:classification"]}]},"bcp-05-x-02":{"x_patch2vuln":{"assumptions":["The tag_version_boundary (v2.5.48, 50 commits after fix) is used as an approximate upper bound for affected versions; exact version boundaries are not explicitly stated in the patch metadata.","PR:L assumes the attacker needs only a basic authenticated MISP account with access to at least one event; higher-privilege roles may be required depending on deployment configuration, but the patch does not specify this.","VC:L assumes the disclosed metadata (event titles, dates, correlation counts) constitutes a low confidentiality impact; in highly sensitive threat-intelligence environments the impact could be rated higher.","CAPEC-126 is the closest available mapping; no CAPEC precisely describes authorization bypass via a stale snapshot in a correlation/join table.","The 'published' flag and distribution/sharing group checks are assumed to be the primary authorization mechanisms in MISP's event model, based on the commit message and patch context.","No public exploit or active exploitation is assumed; the patch does not reference any CVE, advisory, or exploitation evidence."],"capecRationale":[{"capecId":"CAPEC-126","rationale":"The attacker leverages the trusted correlation relationship stored in the correlation table. The system treated the correlation entry as a sufficient authorization basis, but the snapshot data was stale and incomplete (missing published flag), allowing access to event metadata the caller should not see. This is the closest CAPEC to the pattern of relying on a trusted data source that does not reflect current authorization state. Uncertainty: no CAPEC perfectly describes 'stale authorization snapshot in a join table'; CAPEC-126 is the best available match."}],"commit":"2ffa97f0526cd6579b91a4dea560f6246ecbe108","confidence":"medium","credits":[{"lang":"en","type":"reporter","value":"Wenhao Wu"},{"lang":"en","type":"remediation developer","value":"iglocska"},{"lang":"en","type":"remediation developer","value":"Claude Opus 5 (1M context)"}],"cvssRationale":"AV:N: MISP is a network-accessible web application. AC:L: An authenticated user simply requests the related events endpoint; no race condition or complex manipulation is needed. AT:N: No attack-target manipulation required. PR:L: Requires a low-privilege authenticated user with access to at least one event. UI:N: No user interaction needed. VC:L: Disclosure is limited to event metadata (title, date, correlation counts), not full event content or attributes. VI:N, VA:N: No integrity or availability impact. SC:N, SI:N, SA:N: No secondary impacts on other systems. The overall score reflects a low-severity information disclosure requiring authentication.","fixSummary":"The fix enforces proper per-event authorization on the related events query by applying the user's full access-control conditions (including published status, distribution level, and sharing group membership) to the event lookup, rather than relying solely on the stale distribution snapshot stored in the correlation table. 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The patch replaces this with a call to createEventConditions($user), which builds the full set of authorization conditions (published flag, distribution, sharing group), and then adds the Event.id filter on top. The stale comment claiming ACL was enforced via the correlation table was removed. Two files changed, 8 insertions, 9 deletions.","patchTruncated":false,"patches":[{"commit":"2ffa97f0526cd6579b91a4dea560f6246ecbe108","date":"Tue, 22 Sep 2026 15:14:32 +0200","patchSha256":"c315cbcd2cad3e0a5886680a4c6a903d9ed5f3fe3893670f74786cea77a56eb3","source":"https://github.com/MISP/MISP/commit/2ffa97f05.patch","sourceUrl":"https://github.com/MISP/MISP/commit/2ffa97f05.patch","subject":"fix: [security] Scope the related event list to what the"}],"source":"https://github.com/MISP/MISP/commit/2ffa97f05.patch","ssvc":{"options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"Supplier","timestamp":"2026-10-02T15:59:27Z","version":"2.0.3"},"subject":"fix: [security] Scope the related event list to what the","tagVersionBoundary":{"commits_after_fix":50,"repository":"https://github.com/MISP/MISP","tag":"v2.5.48","version":"2.5.48","version_type":"semver"},"weaknessRationale":[{"cweId":"CWE-862","rationale":"The related events query did not apply the caller's per-event authorization checks (published status, distribution, sharing group). The system relied on a stale snapshot in the correlation table instead of re-validating access, effectively omitting the authorization step for the returned events."},{"cweId":"CWE-285","rationale":"Even though some authorization existed (via the correlation table snapshot), it was based on outdated data and lacked the published flag check, making the authorization decision incorrect for events whose access parameters had changed or that were unpublished."}]}},"bcp-05-x-03":{"x_timeline":{"events":[{"description":"Corrective change authored (2ffa97f0526cd6579b91a4dea560f6246ecbe108): fix: [security] Scope the related event list to what the","id":"evt-fix-developed-1","references":["https://github.com/MISP/MISP/commit/2ffa97f05.patch"],"timestamp":"2026-09-22T13:14:32Z","type":"fix-developed"}]}}},"recordType":"advisory","vulnId":"GCVE-1-2026-20165"}]}},"cveMetadata":{"assignerOrgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","assignerShortName":"CIRCL","cveId":"CVE-2026-104910","datePublished":"2026-10-02T16:01:32.781Z","dateReserved":"2026-10-02T16:01:26.599Z","dateUpdated":"2026-10-02T16:01:32.781Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-02 16:16:48","lastModifiedDate":"2026-10-02 16:16:48","problem_types":["CWE-285","CWE-862","CWE-862 CWE-862 Missing Authorization","CWE-285 CWE-285 Improper Authorization"],"metrics":{"cvssMetricV40":[{"source":"5a6e4751-2f3f-4070-9419-94fb35b644e8","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/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","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"LOW","userInteraction":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"ssvcV203":[{"source":"5a6e4751-2f3f-4070-9419-94fb35b644e8","ssvcData":{"timestamp":"2026-10-02T15:59:27Z","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"Supplier","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"104910","Ordinal":"1","Title":"MISP Information Disclosure via Related Events Listing Bypassing","CVE":"CVE-2026-104910","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"104910","Ordinal":"1","NoteData":"MISP contains an authorization bypass in the related events listing functionality. When a user requests the list of events correlated to a given event, the system retrieved related event metadata directly from the correlation table without re-validating the caller's access rights against each related event.\n\nThe correlation table stores a snapshot of the event's distribution level and sharing group at the time the correlation was created, and does not carry the published flag. As a result, events that the caller is not permitted to open—because they are unpublished, or because their distribution or sharing group has changed since the correlation was recorded—were still returned with their metadata (title, date, correlating value counts).\n\nPreconditions:\n\n- An authenticated user with access to at least one event in MISP.\n\n- The existence of correlation entries linking that event to other events the user should not be able to view.\n\nImpact:\n\n- Unauthorized disclosure of event metadata (titles, dates, correlation counts) for events the user has no right to access.\n\n- Potential reconnaissance of threat-intelligence event names and timelines across sharing groups.\n\nAffected: MISP versions prior to the fix commit (2ffa97f05).","Type":"Description","Title":"MISP Information Disclosure via Related Events Listing Bypassing"}]}}}