{"api_version":"1","generated_at":"2026-05-03T12:43:01+00:00","cve":"CVE-2026-31772","urls":{"html":"https://cve.report/CVE-2026-31772","api":"https://cve.report/api/cve/CVE-2026-31772.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-31772","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31772"},"summary":{"title":"Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\n\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\nBIS entries.  However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31)\nentries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller\nhci_conn_big_create_sync().  When conn->num_bis is between 18 and 31,\nthe memcpy that copies conn->bis into cp->bis writes up to 14 bytes\npast the stack buffer, corrupting adjacent stack memory.\n\nThis is trivially reproducible: binding an ISO socket with\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\neventually trigger hci_le_big_create_sync() from the HCI command\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\n\n  BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\n  Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\n\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\nconn->bis can actually carry.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-01 15:16:40","updated_at":"2026-05-03 07:16:20"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe","name":"https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9","name":"https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488","name":"https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0","name":"https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-31772","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31772","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 91d19383b7ed035e22165ae5c836e50bb9f95fbe f5d446624345d309e7a4a1b27ea9f028d6a8c5d9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42ecf1947135110ea08abeaca39741636f9a2285 aba0aea354015794e8312dd7efe726967e58aefe git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42ecf1947135110ea08abeaca39741636f9a2285 eaf32002ca7b1ba51c9f140991fd9febe6de79f0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 42ecf1947135110ea08abeaca39741636f9a2285 bc39a094730ce062fa034a529c93147c096cb488 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.13","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.81 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.22 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.12 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"31772","cve":"CVE-2026-31772","epss":"0.000180000","percentile":"0.046600000","score_date":"2026-05-02","updated_at":"2026-05-03 00:00:23"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/bluetooth/hci_sync.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"f5d446624345d309e7a4a1b27ea9f028d6a8c5d9","status":"affected","version":"91d19383b7ed035e22165ae5c836e50bb9f95fbe","versionType":"git"},{"lessThan":"aba0aea354015794e8312dd7efe726967e58aefe","status":"affected","version":"42ecf1947135110ea08abeaca39741636f9a2285","versionType":"git"},{"lessThan":"eaf32002ca7b1ba51c9f140991fd9febe6de79f0","status":"affected","version":"42ecf1947135110ea08abeaca39741636f9a2285","versionType":"git"},{"lessThan":"bc39a094730ce062fa034a529c93147c096cb488","status":"affected","version":"42ecf1947135110ea08abeaca39741636f9a2285","versionType":"git"},{"status":"affected","version":"8958e1cee4e2eac1a5b825caa4dd96ce9ed975dd","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/bluetooth/hci_sync.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.13"},{"lessThan":"6.13","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.81","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.22","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.81","versionStartIncluding":"6.12.2","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.22","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.12","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","versionStartIncluding":"6.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11.11","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\n\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\nBIS entries.  However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31)\nentries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller\nhci_conn_big_create_sync().  When conn->num_bis is between 18 and 31,\nthe memcpy that copies conn->bis into cp->bis writes up to 14 bytes\npast the stack buffer, corrupting adjacent stack memory.\n\nThis is trivially reproducible: binding an ISO socket with\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\neventually trigger hci_le_big_create_sync() from the HCI command\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\n\n  BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\n  Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\n\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\nconn->bis can actually carry."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-05-03T05:45:52.849Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/f5d446624345d309e7a4a1b27ea9f028d6a8c5d9"},{"url":"https://git.kernel.org/stable/c/aba0aea354015794e8312dd7efe726967e58aefe"},{"url":"https://git.kernel.org/stable/c/eaf32002ca7b1ba51c9f140991fd9febe6de79f0"},{"url":"https://git.kernel.org/stable/c/bc39a094730ce062fa034a529c93147c096cb488"}],"title":"Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-31772","datePublished":"2026-05-01T14:15:00.582Z","dateReserved":"2026-03-09T15:48:24.140Z","dateUpdated":"2026-05-03T05:45:52.849Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-01 15:16:40","lastModifiedDate":"2026-05-03 07:16:20","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"31772","Ordinal":"1","Title":"Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_cre","CVE":"CVE-2026-31772","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"31772","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix stack buffer overflow in hci_le_big_create_sync\n\nhci_le_big_create_sync() uses DEFINE_FLEX to allocate a\nstruct hci_cp_le_big_create_sync on the stack with room for 0x11 (17)\nBIS entries.  However, conn->num_bis can hold up to HCI_MAX_ISO_BIS (31)\nentries — validated against ISO_MAX_NUM_BIS (0x1f) in the caller\nhci_conn_big_create_sync().  When conn->num_bis is between 18 and 31,\nthe memcpy that copies conn->bis into cp->bis writes up to 14 bytes\npast the stack buffer, corrupting adjacent stack memory.\n\nThis is trivially reproducible: binding an ISO socket with\nbc_num_bis = ISO_MAX_NUM_BIS (31) and calling listen() will\neventually trigger hci_le_big_create_sync() from the HCI command\nsync worker, causing a KASAN-detectable stack-out-of-bounds write:\n\n  BUG: KASAN: stack-out-of-bounds in hci_le_big_create_sync+0x256/0x3b0\n  Write of size 31 at addr ffffc90000487b48 by task kworker/u9:0/71\n\nFix this by changing the DEFINE_FLEX count from the incorrect 0x11 to\nHCI_MAX_ISO_BIS, which matches the maximum number of BIS entries that\nconn->bis can actually carry.","Type":"Description","Title":"Bluetooth: hci_sync: fix stack buffer overflow in hci_le_big_cre"}]}}}