{"id":"CVE-2026-41210","state":"PUBLISHED","title":"Moonlight Qt: Remote heap buffer overflow in Moonlight Qt H.264 SPS fixup path via crafted seq_parameter_set_id","description":"Moonlight Qt is a GameStream client for Windows, macOS, Linux, and Steam Link. In version 6.1.0 and earlier, after a victim initiates a streaming session to a malicious host, the host can send a crafted H.264 SPS NAL when Moonlight selects a decoder path that does not advertise CAPABILITY_REFERENCE_FRAME_INVALIDATION_AVC. The SPS fixup path in app/streaming/video/ffmpeg.cpp parses the server-provided data with h264bitstream, where attacker-controlled seq_parameter_set_id is used to index the 32-entry sps_table without validation. A value of 32 or greater causes an out-of-bounds write and remote heap corruption in the Moonlight client. The demonstrated impact is a reliable client crash, while code execution is not established. This issue is fixed in version 6.2.0.","publishedAt":"2026-10-12T21:25:03.303Z","updatedAt":"2026-10-13T15:02:18.935Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["moonlight-stream moonlight-qt"],"affected":[{"vendor":"moonlight-stream","product":"moonlight-qt","versions":[{"version":"< 6.2.0","status":"affected"}]}],"references":["https://github.com/moonlight-stream/moonlight-qt/security/advisories/GHSA-5rvh-v25g-vrgv","https://github.com/moonlight-stream/moonlight-qt/commit/3e24a7a1a5369163482ce5a76d5232536e03c53f","https://github.com/moonlight-stream/moonlight-qt/commit/b7adc70ea474f7448c6185081ad9fc87b0b47cf0","https://github.com/moonlight-stream/moonlight-qt/releases/tag/v6.2.0"],"weaknesses":["CWE-787"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/41xxx/CVE-2026-41210.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-41210","state":"PUBLISHED","datePublished":"2026-10-12T21:25:03.303Z","dateUpdated":"2026-10-13T15:02:18.935Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-04-18T02:51:52.975Z"},"containers":{"cna":{"title":"Moonlight Qt: Remote heap buffer overflow in Moonlight Qt H.264 SPS fixup path via crafted seq_parameter_set_id","descriptions":[{"lang":"en","value":"Moonlight Qt is a GameStream client for Windows, macOS, Linux, and Steam Link. In version 6.1.0 and earlier, after a victim initiates a streaming session to a malicious host, the host can send a crafted H.264 SPS NAL when Moonlight selects a decoder path that does not advertise CAPABILITY_REFERENCE_FRAME_INVALIDATION_AVC. The SPS fixup path in app/streaming/video/ffmpeg.cpp parses the server-provided data with h264bitstream, where attacker-controlled seq_parameter_set_id is used to index the 32-entry sps_table without validation. A value of 32 or greater causes an out-of-bounds write and remote heap corruption in the Moonlight client. The demonstrated impact is a reliable client crash, while code execution is not established. This issue is fixed in version 6.2.0."}],"affected":[{"vendor":"moonlight-stream","product":"moonlight-qt","versions":[{"version":"< 6.2.0","status":"affected"}]}],"references":[{"url":"https://github.com/moonlight-stream/moonlight-qt/security/advisories/GHSA-5rvh-v25g-vrgv","name":"https://github.com/moonlight-stream/moonlight-qt/security/advisories/GHSA-5rvh-v25g-vrgv","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/moonlight-stream/moonlight-qt/commit/3e24a7a1a5369163482ce5a76d5232536e03c53f","name":"https://github.com/moonlight-stream/moonlight-qt/commit/3e24a7a1a5369163482ce5a76d5232536e03c53f","tags":["x_refsource_MISC"]},{"url":"https://github.com/moonlight-stream/moonlight-qt/commit/b7adc70ea474f7448c6185081ad9fc87b0b47cf0","name":"https://github.com/moonlight-stream/moonlight-qt/commit/b7adc70ea474f7448c6185081ad9fc87b0b47cf0","tags":["x_refsource_MISC"]},{"url":"https://github.com/moonlight-stream/moonlight-qt/releases/tag/v6.2.0","name":"https://github.com/moonlight-stream/moonlight-qt/releases/tag/v6.2.0","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-787","lang":"en","description":"CWE-787: Out-of-bounds Write","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-12T21:25:03.303Z"},"source":{"advisory":"GHSA-5rvh-v25g-vrgv","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-13T15:02:04.501291Z","id":"CVE-2026-41210","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-13T15:02:18.935Z"}}]}}}