In MISP, the CollectionsController add() method enforced the sharing-group usability authorization check and element capture only when the HTTP request method was POST. However, the underlying CRUDComponent::add() method persists data on both POST and PUT requests. As a result, an authenticated user could issue a PUT request to the collections/add endpoint, bypassing the sharing-group authorization check entirely. This allowed the creation of a collection with distribution=4 (shared with a specific sharing group) targeting a sharing group that the user was not authorized to use. The bypassed check would normally verify that the current user has access to the specified sharing group before allowing the collection to be associated with it.
The security impact is that an authenticated user can place collection data into a sharing group context they do not have legitimate access to, potentially exposing that data to all members of the unauthorized sharing group and violating the intended access-control boundaries of the MISP instance.
The vulnerability requires an authenticated session and knowledge of a valid sharing group identifier; no user interaction or special tooling is needed beyond sending a PUT request instead of a POST request to the same endpoint.
"}],"value":"In MISP, the CollectionsController add() method enforced the sharing-group usability authorization check and element capture only when the HTTP request method was POST. However, the underlying CRUDComponent::add() method persists data on both POST and PUT requests. As a result, an authenticated user could issue a PUT request to the collections/add endpoint, bypassing the sharing-group authorization check entirely. This allowed the creation of a collection with distribution=4 (shared with a specific sharing group) targeting a sharing group that the user was not authorized to use. The bypassed check would normally verify that the current user has access to the specified sharing group before allowing the collection to be associated with it.\n\nThe security impact is that an authenticated user can place collection data into a sharing group context they do not have legitimate access to, potentially exposing that data to all members of the unauthorized sharing group and violating the intended access-control boundaries of the MISP instance.\n\nThe vulnerability requires an authenticated session and knowledge of a valid sharing group identifier; no user interaction or special tooling is needed beyond sending a PUT request instead of a POST request to the same endpoint."}],"impacts":[{"capecId":"CAPEC-114","descriptions":[{"lang":"en","value":"CAPEC-114 Parameter Tampering"}]}],"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":"LOW","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","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":"2026-09-22T13:20:25.683Z","orgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","shortName":"CIRCL"},"references":[{"name":"Security patch","tags":["patch"],"url":"https://github.com/MISP/MISP/commit/c20f5a836"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"The authorization guard in CollectionsController::add() was extended to cover PUT requests in addition to POST requests. The sharing-group usability check (which validates that the current user can use the target sharing group) and the element capture logic now execute regardless of whether the request arrives as POST or PUT, ensuring that CRUDComponent::add() cannot persist a collection with an unauthorized sharing group via either HTTP verb.
"}],"value":"The authorization guard in CollectionsController::add() was extended to cover PUT requests in addition to POST requests. The sharing-group usability check (which validates that the current user can use the target sharing group) and the element capture logic now execute regardless of whether the request arrives as POST or PUT, ensuring that CRUDComponent::add() cannot persist a collection with an unauthorized sharing group via either HTTP verb."}],"title":"MISP Collections: Missing Authorization Check for Sharing Group on PUT Request in collections/add","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 affected version boundary is inferred from the tag_version_boundary metadata (v2.5.47 with 54 commits after fix); the exact last affected version and first fixed version are not explicitly stated in the patch and may differ.","The CVSS assumes the primary impact is integrity (unauthorized placement of data in a sharing group) rather than confidentiality, since the data in the collection is user-created. If the collection grants read access to other data in the sharing group, the confidentiality impact could be higher.","CAPEC-114 (Parameter Tampering) is the closest available CAPEC for bypassing an authorization check by altering the HTTP method; no CAPEC specifically models HTTP-verb-based authorization bypass.","The patch does not include version tags or release notes; affected version ranges are approximate.","The Co-Authored-By line references an AI assistant (Claude Opus 4.8); it is credited as a tool rather than a human remediation developer."],"capecRationale":[{"capecId":"CAPEC-114","rationale":"The attacker manipulates the HTTP method parameter (changing POST to PUT) to bypass the authorization check that is keyed on the method. The HTTP method acts as a routing parameter that the application uses to decide whether to enforce authorization; tampering with it causes the check to be skipped. This is the closest CAPEC to the observed bypass technique, though the pattern is more specifically an authorization bypass via method selection rather than classic parameter tampering. Uncertainty: no CAPEC specifically covers 'bypassing authorization by altering the HTTP verb'; CAPEC-114 is the best available match."}],"commit":"c20f5a83621de6c534847e1728a1f5af843079b7","confidence":"medium","credits":[{"lang":"en","type":"reporter","value":"Jeroen Pinoy"},{"lang":"en","type":"remediation developer","value":"iglocska"},{"lang":"en","type":"remediation developer","value":"Claude Opus 4.8"}],"cvssRationale":"AV:N - MISP is a web application accessible over the network. AC:L - The attack requires only changing the HTTP method from POST to PUT; no race conditions, complex payloads, or special conditions are needed. AT:N - No attack target manipulation is required. PR:L - An authenticated MISP user is required; the vulnerability is in the authorization layer, not authentication. UI:N - No victim interaction is needed. VC:N - The primary data in the collection is user-created; the vulnerability does not directly expose other users' data to the attacker. VI:L - The attacker can create a collection in a sharing group they are not authorized to use, violating the integrity of the sharing-group access model. VA:N - No availability impact. SC:N - No secondary confidentiality impact identified. SI:L - Secondary integrity impact: data is placed in an unauthorized sharing-group context, potentially visible to that group's members. SA:N - No secondary availability impact.","fixSummary":"The authorization guard in CollectionsController::add() was extended to cover PUT requests in addition to POST requests. The sharing-group usability check (which validates that the current user can use the target sharing group) and the element capture logic now execute regardless of whether the request arrives as POST or PUT, ensuring that CRUDComponent::add() cannot persist a collection with an unauthorized sharing group via either HTTP verb.","generatedAt":"2026-09-22T13:13:03.522587Z","generator":"patch2vuln.py","model":"qwen3.8:27b","modelComparison":{"rankings":[{"agreementScore":9,"assumptionCount":5,"confidence":"medium","model":"qwen3.8:27b","score":5}],"selectedModel":"qwen3.8:27b","selectionMethod":"deterministic-consensus-v1","selectionNotice":"The selected result is closest to model consensus; this heuristic does not establish factual correctness and human review remains required."},"patchSha256":"a49bc540d4465370f1ecbf71f09c9aa51e3a77f3c196f60ddea7210f17f8b1a7","patchSummary":"In app/Controller/CollectionsController.php, the condition guarding the sharing-group authorization check and element capture was changed from 'if ($this->request->is('post'))' to 'if ($this->request->is('post') || $this->request->is('put'))'. A comment was added explaining that CRUDComponent::add() persists on either verb, so the guard must cover both. Four lines inserted, one line deleted in total.","patchTruncated":false,"patches":[{"commit":"c20f5a83621de6c534847e1728a1f5af843079b7","patchSha256":"a49bc540d4465370f1ecbf71f09c9aa51e3a77f3c196f60ddea7210f17f8b1a7","source":"https://github.com/MISP/MISP/commit/c20f5a836.patch","sourceUrl":"https://github.com/MISP/MISP/commit/c20f5a836.patch","subject":"fix: [security] Authorise the collection sharing group on PUT"}],"source":"https://github.com/MISP/MISP/commit/c20f5a836.patch","subject":"fix: [security] Authorise the collection sharing group on PUT","tagVersionBoundary":{"commits_after_fix":54,"repository":"https://github.com/MISP/MISP","tag":"v2.5.47","version":"2.5.47","version_type":"semver"},"weaknessRationale":[{"cweId":"CWE-862","rationale":"The sharing-group usability authorization check was present for POST but entirely absent for PUT requests to the same endpoint. The authorization logic was not missing in design; it was simply not applied to one of the HTTP methods that triggers the same persistence path, resulting in a missing authorization enforcement for PUT."},{"cweId":"CWE-285","rationale":"The application performed an authorization check (sharing-group usability) but applied it conditionally based on the HTTP method, allowing an attacker to bypass the check by selecting a different method. This is an improper authorization implementation where the check is not consistently enforced across all code paths that lead to the sensitive operation."}]}}},"recordType":"advisory","vulnId":"GCVE-1-2026-20271"}]}},"cveMetadata":{"assignerOrgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","assignerShortName":"CIRCL","cveId":"CVE-2026-95671","datePublished":"2026-09-22T13:20:25.683Z","dateReserved":"2026-09-22T13:20:20.466Z","dateUpdated":"2026-09-22T15:32:21.567Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-22 14:17:21","lastModifiedDate":"2026-09-22 16:18:22","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:N/VI:L/VA:N/SC:N/SI:L/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":"NONE","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"LOW","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":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-09-22T15:32:15.165861Z","id":"CVE-2026-95671","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"95671","Ordinal":"1","Title":"MISP Collections: Missing Authorization Check for Sharing Group ","CVE":"CVE-2026-95671","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"95671","Ordinal":"1","NoteData":"In MISP, the CollectionsController add() method enforced the sharing-group usability authorization check and element capture only when the HTTP request method was POST. However, the underlying CRUDComponent::add() method persists data on both POST and PUT requests. As a result, an authenticated user could issue a PUT request to the collections/add endpoint, bypassing the sharing-group authorization check entirely. This allowed the creation of a collection with distribution=4 (shared with a specific sharing group) targeting a sharing group that the user was not authorized to use. The bypassed check would normally verify that the current user has access to the specified sharing group before allowing the collection to be associated with it.\n\nThe security impact is that an authenticated user can place collection data into a sharing group context they do not have legitimate access to, potentially exposing that data to all members of the unauthorized sharing group and violating the intended access-control boundaries of the MISP instance.\n\nThe vulnerability requires an authenticated session and knowledge of a valid sharing group identifier; no user interaction or special tooling is needed beyond sending a PUT request instead of a POST request to the same endpoint.","Type":"Description","Title":"MISP Collections: Missing Authorization Check for Sharing Group "}]}}}