CVE-2026-111758

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{"affected": [{"affectedData": [{"product": "markdown-it", "vendor": "markdown-it", "versions": [{"status": "affected", "version": ">= 14.1.0, < 14.3.3"}, {"status": "affected", "version": ">= 15.0.0, < 15.0.3"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "markdown-it is a Markdown parser. From versions 14.1.0 to before 14.3.3, and 15.0.0 to before 15.0.3, a link reference definition whose label or title is never closed is O(n\u00b2) with default options. Continuation lines are pulled lazily with str += lineContent in src/rules_block/reference.ts, and the subsequent charCodeAt and slice calls flatten the V8 cons-string, copying everything collected so far; this runs before the rule decides the definition is invalid. No options are required to trigger it. This issue has been patched in versions 14.3.3 and 15.0.3."}], "id": "CVE-2026-111758", "lastModified": "2026-10-28T17:17:39.977", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-111758", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-28T16:39:57.942731Z", "version": "2.0.3"}}]}, "published": "2026-10-20T21:17:17.110", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/markdown-it/markdown-it/commit/48fbc465812c440020c663f040ab22deaf8f1eca"}, {"source": "security-advisories@github.com", "url": "https://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503"}, {"source": "security-advisories@github.com", "url": "https://github.com/markdown-it/markdown-it/releases/tag/14.3.3"}, {"source": "security-advisories@github.com", "url": "https://github.com/markdown-it/markdown-it/releases/tag/15.0.3"}, {"source": "security-advisories@github.com", "url": "https://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-407"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "markdown-it: markdown-it: Denial of Service via unclosed link reference definitions", "id": "2556455", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2556455"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-1046", "details": ["A flaw was found in markdown-it. A remote attacker can cause a Denial of Service (DoS) by providing specially crafted Markdown input that contains an unclosed link reference definition spanning multiple lines. Processing this input triggers excessive CPU consumption due to inefficient string handling, which can cause the application to hang and become unresponsive to other users."], "mitigation": {"lang": "en:us", "value": "--- CME Mitigation Guidance (2026-10-20) ---\nDisclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.\nThe highest-value action is to disable the markdown-it reference block rule or avoid lazy string concatenation during multi-line link reference parsing: upgrade to markdown-it 14.3.3 and 15.0.3 (or the fixed Libgit/Forgejo/Ansible/Libgit2/Nextcloud/Markdownlint Cli/Rhoai/Odh Workbench Codeserver Datascience Cpu Py312 Rhel/Rhdh/Rhdh Hub Rhel/Devspaces/Code Rhel/Devspaces/Openvsx Rhel/Devspaces/Pluginregistry Rhel/Thrift/Ansible Automation Platform/Automation Portal/Rhoai/Odh Feature Server Rhel/Rhdh/Red Hat Developer Hub Backstage Plugin Orchestrator Backend/Ansible Automation Platform/Bootc Automation Portal Rhel/Rh Podman Desktop/Rhdh/Red Hat Developer Hub Backstage Plugin Lightspeed Backend/Redhat User Workloads/Mintmaker Renovate Image builds), which scan the source string directly by index position and enforce a 999-character limit on reference labels instead of lazily concatenating continuation lines, closing all 2 injection vectors (crafted multi-line unclosed link reference label, crafted multi-line unclosed link reference title). Until patched, this is a concern on applications parsing untrusted user-supplied Markdown with the reference block rule enabled, so disable the reference rule via configuration or restrict untrusted user Markdown input parsing. As a compensating measure, set per-process CPU time limits via RLIMIT_CPU to bound excessive processing time from quadratic string flattening and apply rate limiting and connection throttling to restrict repeated parsing requests. These controls limit blast radius and contain exploitation, but they do not fix the underlying quadratic cons-string flattening defect \u2014 apply the upstream patch to fully remediate.\nHighest-impact CME: CME-1316 Algorithmic Complexity Safeguards (Pattern/Regex Execution Limits) (high)"}, "name": "CVE-2026-111758", "package_state": [{"cpe": "cpe:/a:redhat:podman_desktop:1", "fix_state": "Affected", "package_name": "rh-podman-desktop", "product_name": "Red Hat Build of Podman Desktop"}, {"cpe": "cpe:/a:redhat:ceph_storage:9", "fix_state": "Affected", "package_name": "thrift", "product_name": "Red Hat Ceph Storage 9"}, {"cpe": "cpe:/a:redhat:rhdh:1", "fix_state": "Affected", "package_name": "rhdh/red-hat-developer-hub-backstage-plugin-lightspeed-backend", "product_name": "Red Hat Developer Hub"}, {"cpe": "cpe:/a:redhat:rhdh:1", "fix_state": "Affected", "package_name": "rhdh/red-hat-developer-hub-backstage-plugin-orchestrator-backend", "product_name": "Red Hat Developer Hub"}, {"cpe": "cpe:/a:redhat:rhdh:1", "fix_state": "Affected", "package_name": "rhdh/rhdh-hub-rhel9", "product_name": "Red Hat Developer Hub"}, {"cpe": "cpe:/a:redhat:hummingbird:1", "fix_state": "Affected", "package_name": "libgit2_1.9", "product_name": "Red Hat Hardened Images"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-feature-server-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_ai", "fix_state": "Affected", "package_name": "rhoai/odh-workbench-codeserver-datascience-cpu-py312-rhel9", "product_name": "Red Hat OpenShift AI (RHOAI)"}, {"cpe": "cpe:/a:redhat:openshift_devspaces:3", "fix_state": "Affected", "package_name": "devspaces/code-rhel9", "product_name": "Red Hat OpenShift Dev Spaces"}, {"cpe": "cpe:/a:redhat:openshift_devspaces:3", "fix_state": "Affected", "package_name": "devspaces/openvsx-rhel9", "product_name": "Red Hat OpenShift Dev Spaces"}, {"cpe": "cpe:/a:redhat:openshift_devspaces:3", "fix_state": "Affected", "package_name": "devspaces/pluginregistry-rhel9", "product_name": "Red Hat OpenShift Dev Spaces"}, {"cpe": "cpe:/a:redhat:ansible_portal:2", "fix_state": "Affected", "package_name": "ansible-automation-platform/automation-portal", "product_name": "Self-service automation portal 2"}, {"cpe": "cpe:/a:redhat:ansible_portal:2", "fix_state": "Affected", "package_name": "ansible-automation-platform/bootc-automation-portal-rhel9", "product_name": "Self-service automation portal 2"}], "public_date": "2026-10-20T20:28:40Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-111758\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-111758\nhttps://github.com/markdown-it/markdown-it/commit/48fbc465812c440020c663f040ab22deaf8f1eca\nhttps://github.com/markdown-it/markdown-it/commit/d99f48839d37af6fd8a2617516c43dab90755503\nhttps://github.com/markdown-it/markdown-it/releases/tag/14.3.3\nhttps://github.com/markdown-it/markdown-it/releases/tag/15.0.3\nhttps://github.com/markdown-it/markdown-it/security/advisories/GHSA-gfr2-rv44-r23c"], "threat_severity": "Important"}

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