CVE-2026-33983

#include <stdio.h> #include <stdint.h> // PoC Code snippet simulating the logic of CVE-2026-33983 // This simulates the behavior in progressive_decompress_tile_upgrade // Mock function to simulate the mismatch detection int progressive_rfx_quant_cmp_equal_mock() { // Returns 0 to simulate a detected mismatch return 0; } void vulnerable_function_simulation() { printf("[VULNERABLE FUNCTION START]\n"); // Step 1: Check for mismatch (simulating progressive_rfx_quant_cmp_equal) if (!progressive_rfx_quant_cmp_equal_mock()) { // Vulnerability: Code only logs a warning but continues execution printf("WLog_WARN: Quantization mismatch detected, but continuing...\n"); } // Step 2: Execution continues with the wrapped value // In the real vulnerability, a value of 247 is used as a shift exponent uint32_t wrapped_value = 247; uint32_t base = 1; printf("Attempting shift operation with exponent: %u\n", wrapped_value); // Step 3: Undefined Behavior / Massive Loop trigger // Note: '1 << 247' is undefined behavior in C for 32-bit integers. // In the actual FreeRDP code, this leads to a loop condition causing ~80 billion iterations. // We simulate the impact description here. // To avoid hanging the system during this demonstration, we comment out the actual UB line. // uint32_t result = base << wrapped_value; printf("[IMPACT] This would trigger a loop of ~80 billion iterations (CPU DoS).\n"); printf("[VULNERABLE FUNCTION END]\n"); } int main() { vulnerable_function_simulation(); return 0; }

{"cve": {"id": "CVE-2026-33983", "sourceIdentifier": "[email protected]", "published": "2026-03-30T22:16:19.407", "lastModified": "2026-04-01T20:03:24.513", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, progressive_decompress_tile_upgrade() detects a mismatch via progressive_rfx_quant_cmp_equal() but only emits WLog_WARN, execution continues. The wrapped value (247) is used as a shift exponent, causing undefined behavior and an approximately 80 billion iteration loop (CPU DoS). This issue has been patched in version 3.24.2."}, {"lang": "es", "value": "FreeRDP es una implementación gratuita del Protocolo de Escritorio Remoto. Antes de la versión 3.24.2, progressive_decompress_tile_upgrade() detecta una discrepancia a través de progressive_rfx_quant_cmp_equal() pero solo emite WLog_WARN, la ejecución continúa. El valor envuelto (247) se utiliza como exponente de desplazamiento, causando un comportamiento indefinido y un bucle de aproximadamente 80 mil millones de iteraciones (DoS de CPU). Este problema ha sido parcheado en la versión 3.24.2."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-190"}, {"lang": "en", "value": "CWE-252"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.24.2", "matchCriteriaId": "03FF152C-C651-4586-8958-1555D9797516"}]}]}], "references": [{"url": "https://github.com/FreeRDP/FreeRDP/commit/78188ab479c8e6eb9ba2475b3732c76b4bbe5425", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4gfm-4p52-h478", "source": "[email protected]", "tags": ["Patch", "Vendor Advisory"]}]}}