{"id":"CVE-2026-42859","state":"PUBLISHED","title":"Neat VNC: Buffer overflow due to oversized RSA public keys","description":"Neat VNC is a VNC server library. Prior to 0.9.6, a pre-authentication stack buffer overflow exists in neatvnc in the RSA-AES security type handler. An unauthenticated remote attacker who can reach the VNC listening socket can send a crafted security type 5 (RSA-AES) or security type 129 (RSA-AES-256) handshake with an oversized client RSA public key, causing rsa_aes_send_challenge in src/auth/rsa-aes.c to overflow a 1024-byte on-stack buffer when encrypting the server challenge. This results in at least a denial of service via server crash. This vulnerability is fixed in 0.9.6.","publishedAt":"2026-05-11T17:36:08.143Z","updatedAt":"2026-05-11T18:22:03.144Z","severity":{"score":8.1,"label":"High","version":"4.0","vector":"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","source":"GitHub_M"},"assigner":"GitHub_M","products":["any1 neatvnc"],"affected":[{"vendor":"any1","product":"neatvnc","versions":[{"version":"< 0.9.6","status":"affected"}]}],"references":["https://github.com/any1/neatvnc/security/advisories/GHSA-567c-gpv8-qh9h","https://github.com/any1/neatvnc/commit/1f6cd6b75cc167fed3a19a9d1552a1f662f6b337"],"weaknesses":["CWE-120"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/42xxx/CVE-2026-42859.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-42859","state":"PUBLISHED","datePublished":"2026-05-11T17:36:08.143Z","dateUpdated":"2026-05-11T18:22:03.144Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-30T16:44:48.379Z"},"containers":{"cna":{"title":"Neat VNC: Buffer overflow due to oversized RSA public keys","descriptions":[{"lang":"en","value":"Neat VNC is a VNC server library. Prior to 0.9.6, a pre-authentication stack buffer overflow exists in neatvnc in the RSA-AES security type handler. An unauthenticated remote attacker who can reach the VNC listening socket can send a crafted security type 5 (RSA-AES) or security type 129 (RSA-AES-256) handshake with an oversized client RSA public key, causing rsa_aes_send_challenge in src/auth/rsa-aes.c to overflow a 1024-byte on-stack buffer when encrypting the server challenge. This results in at least a denial of service via server crash. This vulnerability is fixed in 0.9.6."}],"affected":[{"vendor":"any1","product":"neatvnc","versions":[{"version":"< 0.9.6","status":"affected"}]}],"references":[{"url":"https://github.com/any1/neatvnc/security/advisories/GHSA-567c-gpv8-qh9h","name":"https://github.com/any1/neatvnc/security/advisories/GHSA-567c-gpv8-qh9h","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/any1/neatvnc/commit/1f6cd6b75cc167fed3a19a9d1552a1f662f6b337","name":"https://github.com/any1/neatvnc/commit/1f6cd6b75cc167fed3a19a9d1552a1f662f6b337","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.1,"baseSeverity":"HIGH","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","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-120","lang":"en","description":"CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-05-11T17:36:08.143Z"},"source":{"advisory":"GHSA-567c-gpv8-qh9h","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-11T18:21:36.453865Z","id":"CVE-2026-42859","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-11T18:22:03.144Z"}}]}}}