{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-112991", "assignerOrgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "state": "PUBLISHED", "assignerShortName": "CIRCL", "dateReserved": "2026-10-19T22:19:44.187Z", "datePublished": "2026-10-19T22:19:50.011Z", "dateUpdated": "2026-10-20T19:22:15.189Z"}, "containers": {"cna": {"affected": [{"cpes": ["cpe:2.3:a:misp:misp_modules_\\(html_to_markdown_expansion_module\\):*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["misp_modules/modules/expansion/html_to_markdown.py"], "product": "misp-modules", "programFiles": ["misp_modules/modules/expansion/html_to_markdown.py"], "repo": "https://github.com/misp/misp-modules", "vendor": "MISP", "versions": [{"lessThanOrEqual": "3.0.12", "status": "affected", "version": "0", "versionType": "semver"}]}], "credits": [{"lang": "en", "type": "remediation developer", "value": "elhoim"}, {"lang": "en", "type": "remediation developer", "value": "Claude Opus 5 (1M context)"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>The html_to_markdown expansion module in MISP Modules contains a server-side request forgery (SSRF) vulnerability in its is_safe_url() URL validation function. The BLOCKED_RANGES list used to reject unsafe destination addresses was incomplete, omitting several critical IP address ranges. Specifically, the following ranges were not blocked: 0.0.0.0/8 (unspecified, which routes to loopback on Linux), 100.64.0.0/10 (carrier-grade NAT per RFC 6598), ::/128 (IPv6 unspecified), fc00::/7 (IPv6 Unique Local Addresses), and fe80::/10 (IPv6 link-local). The existing list only covered IPv4 loopback (127.0.0.0/8), RFC 1918 private ranges, IPv4 link-local (169.254.0.0/16), and IPv6 loopback (::1/128).</p><p>An authenticated user with the ability to create or modify MISP attributes that trigger the html_to_markdown expansion module could supply URLs pointing to these unblocked internal address ranges. Because the module fetches the URL server-side to convert HTML content to Markdown, the request is made from the MISP server's network context. This allows an attacker to probe and read responses from internal services, carrier-grade NAT infrastructure, or link-local endpoints that would otherwise be unreachable from external networks. IPv4-mapped IPv6 forms (e.g., [::ffff:0.0.0.0]) also bypassed the existing checks.</p><p>The security impact is primarily confidentiality: an attacker can read data served by internal services reachable from the MISP server. The MISP instance itself is not compromised, but it is abused as a proxy to access otherwise restricted network resources.</p>"}], "value": "The html_to_markdown expansion module in MISP Modules contains a server-side request forgery (SSRF) vulnerability in its is_safe_url() URL validation function. The BLOCKED_RANGES list used to reject unsafe destination addresses was incomplete, omitting several critical IP address ranges. Specifically, the following ranges were not blocked: 0.0.0.0/8 (unspecified, which routes to loopback on Linux), 100.64.0.0/10 (carrier-grade NAT per RFC 6598), ::/128 (IPv6 unspecified), fc00::/7 (IPv6 Unique Local Addresses), and fe80::/10 (IPv6 link-local). The existing list only covered IPv4 loopback (127.0.0.0/8), RFC 1918 private ranges, IPv4 link-local (169.254.0.0/16), and IPv6 loopback (::1/128).\n\nAn authenticated user with the ability to create or modify MISP attributes that trigger the html_to_markdown expansion module could supply URLs pointing to these unblocked internal address ranges. Because the module fetches the URL server-side to convert HTML content to Markdown, the request is made from the MISP server's network context. This allows an attacker to probe and read responses from internal services, carrier-grade NAT infrastructure, or link-local endpoints that would otherwise be unreachable from external networks. IPv4-mapped IPv6 forms (e.g., [::ffff:0.0.0.0]) also bypassed the existing checks.\n\nThe security impact is primarily confidentiality: an attacker can read data served by internal services reachable from the MISP server. 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The existing IPv4-mapped IPv6 normalisation logic ensures that mapped forms (e.g., ::ffff:0.0.0.0) are also blocked. Regression tests are added covering both literal IP addresses in URLs and hostnames that resolve to the newly blocked ranges.</p>"}], "value": "The fix extends the BLOCKED_RANGES list in is_safe_url() to include the previously missing IP address ranges: 0.0.0.0/8, 100.64.0.0/10, ::/128, fc00::/7, and fe80::/10. The existing IPv4-mapped IPv6 normalisation logic ensures that mapped forms (e.g., ::ffff:0.0.0.0) are also blocked. Regression tests are added covering both literal IP addresses in URLs and hostnames that resolve to the newly blocked ranges."}], "source": {"discovery": "UNKNOWN"}, "title": "MISP html_to_markdown Module SSRF via Incomplete IP Range Blocking in is_safe_url()", "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": "partial", "scope": "record", "tags": ["ai-computer-assisted:llm-generated", "ai-computer-assisted:classification"]}]}, "bcp-05-x-02": {"x_patch2vuln": {"assumptions": ["PR:L assumes that creating or modifying a MISP attribute to trigger the html_to_markdown expansion module requires authenticated access. 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This is the root-cause input validation deficiency enabling the SSRF."}], "tagVersionBoundary": {"tag": "v3.0.13", "version": "3.0.13", "repository": "https://github.com/misp/misp-modules", "version_type": "semver", "commits_after_fix": 139}}}, "bcp-05-x-03": {"x_timeline": {"events": [{"id": "evt-fix-developed-1", "type": "fix-developed", "timestamp": "2026-09-25T22:15:46Z", "references": ["https://github.com/misp/misp-modules/commit/98a1c2c2f297665dd8d4609e9cd644007a57516b.patch"], "description": "Corrective change authored (98a1c2c2f297665dd8d4609e9cd644007a57516b): fix: [html_to_markdown] block unspecified, shared, ULA and"}]}}}, "recordType": "advisory"}], "credits": [{"lang": "en", "type": "remediation developer", "value": "elhoim"}, {"lang": "en", "type": "remediation developer", "value": "Claude Opus 5 (1M context)"}], "impacts": [{"capecId": "CAPEC-12", "descriptions": [{"lang": "en", "value": "CAPEC-12 Server Side Request Forgery"}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}, {"other": {"type": "SSVC", "content": {"role": "Supplier", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-19T22:15:01Z"}}, "format": "SSVC", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"cpes": ["cpe:2.3:a:misp:misp_modules_\\(html_to_markdown_expansion_module\\):*:*:*:*:*:*:*:*"], "repo": "https://github.com/misp/misp-modules", "vendor": "MISP", "modules": ["misp_modules/modules/expansion/html_to_markdown.py"], "product": "misp-modules", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "3.0.12"}], "programFiles": ["misp_modules/modules/expansion/html_to_markdown.py"], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "The fix extends the BLOCKED_RANGES list in is_safe_url() to include the previously missing IP address ranges: 0.0.0.0/8, 100.64.0.0/10, ::/128, fc00::/7, and fe80::/10. The existing IPv4-mapped IPv6 normalisation logic ensures that mapped forms (e.g., ::ffff:0.0.0.0) are also blocked. Regression tests are added covering both literal IP addresses in URLs and hostnames that resolve to the newly blocked ranges.", "supportingMedia": [{"type": "text/html", "value": "<p>The fix extends the BLOCKED_RANGES list in is_safe_url() to include the previously missing IP address ranges: 0.0.0.0/8, 100.64.0.0/10, ::/128, fc00::/7, and fe80::/10. The existing IPv4-mapped IPv6 normalisation logic ensures that mapped forms (e.g., ::ffff:0.0.0.0) are also blocked. Regression tests are added covering both literal IP addresses in URLs and hostnames that resolve to the newly blocked ranges.</p>", "base64": false}]}], "references": [{"url": "https://github.com/misp/misp-modules/commit/98a1c2c2f297665dd8d4609e9cd644007a57516b", "name": "Security patch", "tags": ["patch"]}], "x_generator": {"engine": "Vulnogram 0.2.0"}, "descriptions": [{"lang": "en", "value": "The html_to_markdown expansion module in MISP Modules contains a server-side request forgery (SSRF) vulnerability in its is_safe_url() URL validation function. The BLOCKED_RANGES list used to reject unsafe destination addresses was incomplete, omitting several critical IP address ranges. Specifically, the following ranges were not blocked: 0.0.0.0/8 (unspecified, which routes to loopback on Linux), 100.64.0.0/10 (carrier-grade NAT per RFC 6598), ::/128 (IPv6 unspecified), fc00::/7 (IPv6 Unique Local Addresses), and fe80::/10 (IPv6 link-local). The existing list only covered IPv4 loopback (127.0.0.0/8), RFC 1918 private ranges, IPv4 link-local (169.254.0.0/16), and IPv6 loopback (::1/128).\n\nAn authenticated user with the ability to create or modify MISP attributes that trigger the html_to_markdown expansion module could supply URLs pointing to these unblocked internal address ranges. Because the module fetches the URL server-side to convert HTML content to Markdown, the request is made from the MISP server's network context. This allows an attacker to probe and read responses from internal services, carrier-grade NAT infrastructure, or link-local endpoints that would otherwise be unreachable from external networks. IPv4-mapped IPv6 forms (e.g., [::ffff:0.0.0.0]) also bypassed the existing checks.\n\nThe security impact is primarily confidentiality: an attacker can read data served by internal services reachable from the MISP server. The MISP instance itself is not compromised, but it is abused as a proxy to access otherwise restricted network resources.", "supportingMedia": [{"type": "text/html", "value": "<p>The html_to_markdown expansion module in MISP Modules contains a server-side request forgery (SSRF) vulnerability in its is_safe_url() URL validation function. The BLOCKED_RANGES list used to reject unsafe destination addresses was incomplete, omitting several critical IP address ranges. Specifically, the following ranges were not blocked: 0.0.0.0/8 (unspecified, which routes to loopback on Linux), 100.64.0.0/10 (carrier-grade NAT per RFC 6598), ::/128 (IPv6 unspecified), fc00::/7 (IPv6 Unique Local Addresses), and fe80::/10 (IPv6 link-local). The existing list only covered IPv4 loopback (127.0.0.0/8), RFC 1918 private ranges, IPv4 link-local (169.254.0.0/16), and IPv6 loopback (::1/128).</p><p>An authenticated user with the ability to create or modify MISP attributes that trigger the html_to_markdown expansion module could supply URLs pointing to these unblocked internal address ranges. Because the module fetches the URL server-side to convert HTML content to Markdown, the request is made from the MISP server's network context. This allows an attacker to probe and read responses from internal services, carrier-grade NAT infrastructure, or link-local endpoints that would otherwise be unreachable from external networks. IPv4-mapped IPv6 forms (e.g., [::ffff:0.0.0.0]) also bypassed the existing checks.</p><p>The security impact is primarily confidentiality: an attacker can read data served by internal services reachable from the MISP server. The MISP instance itself is not compromised, but it is abused as a proxy to access otherwise restricted network resources.</p>", "base64": false}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-918", "description": "CWE-918 Server-Side Request Forgery (SSRF)"}]}, {"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-20", "description": "CWE-20 Improper Input Validation"}]}], "providerMetadata": {"orgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "shortName": "CIRCL", "dateUpdated": "2026-10-20T06:02:08.508Z"}}}, "cveMetadata": {"cveId": "CVE-2026-112991", "state": "PUBLISHED", "dateUpdated": "2026-10-20T19:22:15.189Z", "dateReserved": "2026-10-19T22:19:44.187Z", "assignerOrgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "datePublished": "2026-10-19T22:19:50.011Z", "assignerShortName": "CIRCL"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"cpes": ["cpe:2.3:a:misp:misp_modules_\\(html_to_markdown_expansion_module\\):*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["misp_modules/modules/expansion/html_to_markdown.py"], "product": "misp-modules", "programFiles": ["misp_modules/modules/expansion/html_to_markdown.py"], "repo": "https://github.com/misp/misp-modules", "vendor": "MISP", "versions": [{"lessThanOrEqual": "3.0.12", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "The html_to_markdown expansion module in MISP Modules contains a server-side request forgery (SSRF) vulnerability in its is_safe_url() URL validation function. The BLOCKED_RANGES list used to reject unsafe destination addresses was incomplete, omitting several critical IP address ranges. Specifically, the following ranges were not blocked: 0.0.0.0/8 (unspecified, which routes to loopback on Linux), 100.64.0.0/10 (carrier-grade NAT per RFC 6598), ::/128 (IPv6 unspecified), fc00::/7 (IPv6 Unique Local Addresses), and fe80::/10 (IPv6 link-local). The existing list only covered IPv4 loopback (127.0.0.0/8), RFC 1918 private ranges, IPv4 link-local (169.254.0.0/16), and IPv6 loopback (::1/128).\n\nAn authenticated user with the ability to create or modify MISP attributes that trigger the html_to_markdown expansion module could supply URLs pointing to these unblocked internal address ranges. Because the module fetches the URL server-side to convert HTML content to Markdown, the request is made from the MISP server's network context. This allows an attacker to probe and read responses from internal services, carrier-grade NAT infrastructure, or link-local endpoints that would otherwise be unreachable from external networks. IPv4-mapped IPv6 forms (e.g., [::ffff:0.0.0.0]) also bypassed the existing checks.\n\nThe security impact is primarily confidentiality: an attacker can read data served by internal services reachable from the MISP server. The MISP instance itself is not compromised, but it is abused as a proxy to access otherwise restricted network resources."}], "id": "CVE-2026-112991", "lastModified": "2026-10-20T20:17:16.700", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "type": "Secondary"}], "ssvcV203": [{"source": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "ssvcData": {"options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "Supplier", "timestamp": "2026-10-19T22:15:01Z", "version": "2.0.3"}}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-112991", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-20T19:22:04.700266Z", "version": "2.0.3"}}]}, "published": "2026-10-19T23:17:36.350", "references": [{"source": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "url": "https://github.com/misp/misp-modules/commit/98a1c2c2f297665dd8d4609e9cd644007a57516b"}], "sourceIdentifier": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-20"}, {"lang": "en", "value": "CWE-918"}], "source": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "type": "Secondary"}]}

{}