175 lines
7.0 KiB
JSON
175 lines
7.0 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-7831",
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"assignerOrgId": "33c584b5-0579-4c06-b2a0-8d8329fcab9c",
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"state": "PUBLISHED",
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"assignerShortName": "securin",
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"dateReserved": "2026-05-05T04:03:22.622Z",
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"datePublished": "2026-07-01T03:33:25.314Z",
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"dateUpdated": "2026-07-09T04:35:54.891Z"
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},
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"containers": {
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"cna": {
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"title": "UltraVNC viewer off-by-one stack overflow in ServerInit desktop name parsing",
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"descriptions": [
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{
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"lang": "en",
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"value": "UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConnection.cpp, when the server-supplied nameLength equals exactly 2024 the code declares a 2024-byte stack buffer _dn[2024] and calls ReadString(_dn, 2024). ReadString writes the NUL terminator at buf[length], i.e., _dn[2024], one byte past the end of the stack buffer. A malicious VNC server can trigger this condition by advertising a desktop name of length 2024 in its ServerInit message. On release builds without stack canaries the single-byte NUL overwrite adjacent stack data. On builds with /GS stack protection the canary is corrupted and the process terminates, resulting in denial of service. User interaction (connecting the viewer to the malicious server) is required."
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}
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],
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"affected": [
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{
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"vendor": "uvnc",
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"product": "UltraVNC",
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"versions": [
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{
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"version": "0",
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"lessThanOrEqual": "1.8.2.2",
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"status": "affected",
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"versionType": "custom"
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}
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],
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"defaultStatus": "unaffected",
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"modules": [
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"vncviewer"
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]
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}
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],
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"problemTypes": [
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{
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"descriptions": [
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{
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"type": "CWE",
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"cweId": "CWE-193",
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"lang": "en",
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"description": "Off-by-one Error"
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}
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]
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},
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{
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"descriptions": [
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{
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"type": "CWE",
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"cweId": "CWE-787",
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"lang": "en",
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"description": "Out-of-bounds Write"
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}
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]
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}
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],
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"metrics": [
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{
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"format": "CVSS",
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"scenarios": [
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{
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"lang": "en",
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"value": "GENERAL"
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}
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],
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H",
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"attackVector": "NETWORK",
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"attackComplexity": "LOW",
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"privilegesRequired": "NONE",
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"userInteraction": "REQUIRED",
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"scope": "UNCHANGED",
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"confidentialityImpact": "LOW",
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"integrityImpact": "LOW",
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"availabilityImpact": "HIGH",
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"baseScore": 7.5,
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"baseSeverity": "HIGH"
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}
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}
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],
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"references": [
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{
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"url": "https://uvnc.com/",
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"name": "UltraVNC project page",
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"tags": [
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"vendor-advisory"
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]
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},
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{
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"url": "https://github.com/ultravnc/UltraVNC",
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"name": "UltraVNC source repository",
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"tags": [
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"product"
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]
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},
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{
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"url": "https://www.securin.io/zero-days/cve-2026-7831-off-by-one-stack-overflow-viewer-namelength-ultravnc"
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}
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],
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"timeline": [
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{
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"time": "2026-06-02T00:00:00.000Z",
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"lang": "en",
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"value": "Vulnerability discovered during security audit"
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},
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{
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"time": "2026-06-17T00:00:00.000Z",
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"lang": "en",
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"value": "Reported to vendor (coordinated disclosure)"
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},
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{
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"time": "2026-09-15T00:00:00.000Z",
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"lang": "en",
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"value": "Planned public disclosure (90-day window)"
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}
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],
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"credits": [
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{
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"lang": "en",
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"value": "Arjun Basnet, Securin (arjun.basnet@securin.io)",
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"type": "finder"
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}
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],
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"source": {
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"discovery": "EXTERNAL",
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"advisory": "Securin Security Advisory — FINDING-011"
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},
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"providerMetadata": {
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"orgId": "33c584b5-0579-4c06-b2a0-8d8329fcab9c",
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"shortName": "securin",
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"dateUpdated": "2026-07-09T04:35:54.891Z"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"timestamp": "2026-07-01T13:12:22.055256Z",
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"id": "CVE-2026-7831",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "partial"
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}
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],
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"role": "CISA Coordinator",
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"version": "2.0.3"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-07-01T13:12:46.218Z"
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}
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}
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]
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}
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} |