{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-44988", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-05-08T16:23:33.265Z", "datePublished": "2026-05-27T14:26:50.063Z", "dateUpdated": "2026-05-27T14:26:50.063Z"}, "containers": {"cna": {"title": "LibVNCClient Tight Gradient decoding allows malicious server-triggered heap/stack OOB writes", "problemTypes": [{"descriptions": [{"cweId": "CWE-787", "lang": "en", "description": "CWE-787: Out-of-bounds Write", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "version": "3.1"}}], "references": [{"name": "https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58"}, {"name": "https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1", "tags": ["x_refsource_MISC"], "url": "https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1"}], "affected": [{"vendor": "LibVNC", "product": "libvncserver", "versions": [{"version": "<= 0.9.15", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-05-27T14:26:50.063Z"}, "descriptions": [{"lang": "en", "value": "LibVNCClient is a library for easy implementation of a VNC client. In 0.9.15 and earlier, LibVNCClient's Tight encoding decoder uses fixed-size 2048-pixel scratch buffers for the Gradient filter, but it does not reject Tight rectangles whose width is larger than 2048 pixels. A malicious VNC server can send a crafted FramebufferUpdate rectangle using Tight encoding with NoZlib | ExplicitFilter and the Gradient filter. When a LibVNCClient-based client connects, the client processes the server-controlled rectangle width and writes beyond fixed-size Gradient buffers. This vulnerability is fixed with commit 5b270544b85233668b98161323297d418a8f5fd1."}], "source": {"advisory": "GHSA-jcc5-8wj4-7c58", "discovery": "UNKNOWN"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "LibVNCClient is a library for easy implementation of a VNC client. In 0.9.15 and earlier, LibVNCClient's Tight encoding decoder uses fixed-size 2048-pixel scratch buffers for the Gradient filter, but it does not reject Tight rectangles whose width is larger than 2048 pixels. A malicious VNC server can send a crafted FramebufferUpdate rectangle using Tight encoding with NoZlib | ExplicitFilter and the Gradient filter. When a LibVNCClient-based client connects, the client processes the server-controlled rectangle width and writes beyond fixed-size Gradient buffers. This vulnerability is fixed with commit 5b270544b85233668b98161323297d418a8f5fd1."}], "id": "CVE-2026-44988", "lastModified": "2026-05-27T15:16:29.830", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 5.9, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-05-27T15:16:29.830", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1"}, {"source": "security-advisories@github.com", "url": "https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-787"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{"created": "2026-05-27T21:15:25.921719+00:00", "updated": "2026-05-27T21:15:25.921731+00:00", "vendors": []}