{"api_version":"1","generated_at":"2026-06-26T16:42:33+00:00","cve":"CVE-2026-53208","urls":{"html":"https://cve.report/CVE-2026-53208","api":"https://cve.report/api/cve/CVE-2026-53208.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-53208","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-53208"},"summary":{"title":"Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig\n\nnet/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR\nsignaling packets up to the channel MTU and dispatches each command\nwithout enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer\nwithin radio range can send a fixed-channel CID 0x0001 packet that is\nlarger than MTUsig and contains many L2CAP_ECHO_REQ commands before\npairing. In a real-radio stock-kernel run, one 681-byte signaling\npacket containing 168 zero-length ECHO_REQ commands made the target\ntransmit 168 ECHO_RSP frames over about 220 ms.\n\nImpact: a Bluetooth BR/EDR peer within radio range, before pairing, can\nforce 168 ECHO_RSP frames from one 681-byte fixed-channel signaling\npacket containing packed ECHO_REQ commands.\n\nDefine Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and\nreject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP\ncarrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched.\n\nThe Bluetooth Core spec wording for MTUExceeded says the reject\nidentifier shall match the first request command in the packet, and\nthat packets containing only responses shall be silently discarded.\nLinux intentionally deviates from that prescription: silently\ndiscarding desynchronizes the peer because the remote stack never\nlearns its responses were dropped, and locating the first request\ncommand requires walking command headers past MTUsig, i.e. processing\nbytes from a packet we have already decided is too large to process.\nWe therefore always emit one reject and use the identifier from the\nfirst command header, a single fixed-offset byte read.\n\nThe unrestricted BR/EDR signaling parser and ECHO_REQ response path both\ntrace to the initial git import; no later introducing commit is\navailable for a Fixes tag.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-06-25 09:16:38","updated_at":"2026-06-25 09:16:38"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/214a2042b16b3c8d798a8b9ef9f36094f13a9859","name":"https://git.kernel.org/stable/c/214a2042b16b3c8d798a8b9ef9f36094f13a9859","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b20e8a98dd29b121f58fcdf51e8576119aba536a","name":"https://git.kernel.org/stable/c/b20e8a98dd29b121f58fcdf51e8576119aba536a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dd214733544427587a95f66dbf3adff072568990","name":"https://git.kernel.org/stable/c/dd214733544427587a95f66dbf3adff072568990","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e2b8acf9405bd9b1baf1c54dc897b0905db689bf","name":"https://git.kernel.org/stable/c/e2b8acf9405bd9b1baf1c54dc897b0905db689bf","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e05c4ac575b457978a7ef441053394169084869c","name":"https://git.kernel.org/stable/c/e05c4ac575b457978a7ef441053394169084869c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fa5823126239b3e453fac1a2fe50726c7f4a55e1","name":"https://git.kernel.org/stable/c/fa5823126239b3e453fac1a2fe50726c7f4a55e1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab","name":"https://git.kernel.org/stable/c/a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dedc92b96dc1d8919a3bdf2495ede68922ef7ebc","name":"https://git.kernel.org/stable/c/dedc92b96dc1d8919a3bdf2495ede68922ef7ebc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-53208","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53208","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 e05c4ac575b457978a7ef441053394169084869c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 fa5823126239b3e453fac1a2fe50726c7f4a55e1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 b20e8a98dd29b121f58fcdf51e8576119aba536a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 214a2042b16b3c8d798a8b9ef9f36094f13a9859 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.6.143 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.94 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18.36 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 7.0.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.259 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.210 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.176 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.94 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.36 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.13 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"53208","cve":"CVE-2026-53208","epss":"0.001760000","percentile":"0.073580000","score_date":"2026-06-25","updated_at":"2026-06-26 00:06:14"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/net/bluetooth/l2cap.h","net/bluetooth/l2cap_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"e05c4ac575b457978a7ef441053394169084869c","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"fa5823126239b3e453fac1a2fe50726c7f4a55e1","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"b20e8a98dd29b121f58fcdf51e8576119aba536a","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"214a2042b16b3c8d798a8b9ef9f36094f13a9859","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"dedc92b96dc1d8919a3bdf2495ede68922ef7ebc","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"e2b8acf9405bd9b1baf1c54dc897b0905db689bf","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"dd214733544427587a95f66dbf3adff072568990","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"5.10.259","status":"affected","version":"0","versionType":"semver"},{"lessThan":"5.15.210","status":"affected","version":"0","versionType":"semver"},{"lessThan":"6.1.176","status":"affected","version":"0","versionType":"semver"},{"lessThan":"6.6.143","status":"affected","version":"0","versionType":"semver"},{"lessThan":"6.12.94","status":"affected","version":"0","versionType":"semver"},{"lessThan":"6.18.36","status":"affected","version":"0","versionType":"semver"},{"lessThan":"7.0.13","status":"affected","version":"0","versionType":"semver"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/net/bluetooth/l2cap.h","net/bluetooth/l2cap_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.259","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.210","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.176","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.143","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.94","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.36","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.13","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.259","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.210","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.176","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.143","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.94","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.36","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.13","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig\n\nnet/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR\nsignaling packets up to the channel MTU and dispatches each command\nwithout enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer\nwithin radio range can send a fixed-channel CID 0x0001 packet that is\nlarger than MTUsig and contains many L2CAP_ECHO_REQ commands before\npairing. In a real-radio stock-kernel run, one 681-byte signaling\npacket containing 168 zero-length ECHO_REQ commands made the target\ntransmit 168 ECHO_RSP frames over about 220 ms.\n\nImpact: a Bluetooth BR/EDR peer within radio range, before pairing, can\nforce 168 ECHO_RSP frames from one 681-byte fixed-channel signaling\npacket containing packed ECHO_REQ commands.\n\nDefine Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and\nreject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP\ncarrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched.\n\nThe Bluetooth Core spec wording for MTUExceeded says the reject\nidentifier shall match the first request command in the packet, and\nthat packets containing only responses shall be silently discarded.\nLinux intentionally deviates from that prescription: silently\ndiscarding desynchronizes the peer because the remote stack never\nlearns its responses were dropped, and locating the first request\ncommand requires walking command headers past MTUsig, i.e. processing\nbytes from a packet we have already decided is too large to process.\nWe therefore always emit one reject and use the identifier from the\nfirst command header, a single fixed-offset byte read.\n\nThe unrestricted BR/EDR signaling parser and ECHO_REQ response path both\ntrace to the initial git import; no later introducing commit is\navailable for a Fixes tag."}],"providerMetadata":{"dateUpdated":"2026-06-25T08:39:14.257Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/e05c4ac575b457978a7ef441053394169084869c"},{"url":"https://git.kernel.org/stable/c/fa5823126239b3e453fac1a2fe50726c7f4a55e1"},{"url":"https://git.kernel.org/stable/c/b20e8a98dd29b121f58fcdf51e8576119aba536a"},{"url":"https://git.kernel.org/stable/c/214a2042b16b3c8d798a8b9ef9f36094f13a9859"},{"url":"https://git.kernel.org/stable/c/a8335f3db15bd1e0e82e0db5d488fabc7d10d1ab"},{"url":"https://git.kernel.org/stable/c/dedc92b96dc1d8919a3bdf2495ede68922ef7ebc"},{"url":"https://git.kernel.org/stable/c/e2b8acf9405bd9b1baf1c54dc897b0905db689bf"},{"url":"https://git.kernel.org/stable/c/dd214733544427587a95f66dbf3adff072568990"}],"title":"Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-53208","datePublished":"2026-06-25T08:39:14.257Z","dateReserved":"2026-06-09T07:44:35.391Z","dateUpdated":"2026-06-25T08:39:14.257Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-06-25 09:16:38","lastModifiedDate":"2026-06-25 09:16:38","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"53208","Ordinal":"1","Title":"Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig","CVE":"CVE-2026-53208","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"53208","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig\n\nnet/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR\nsignaling packets up to the channel MTU and dispatches each command\nwithout enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer\nwithin radio range can send a fixed-channel CID 0x0001 packet that is\nlarger than MTUsig and contains many L2CAP_ECHO_REQ commands before\npairing. In a real-radio stock-kernel run, one 681-byte signaling\npacket containing 168 zero-length ECHO_REQ commands made the target\ntransmit 168 ECHO_RSP frames over about 220 ms.\n\nImpact: a Bluetooth BR/EDR peer within radio range, before pairing, can\nforce 168 ECHO_RSP frames from one 681-byte fixed-channel signaling\npacket containing packed ECHO_REQ commands.\n\nDefine Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and\nreject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP\ncarrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched.\n\nThe Bluetooth Core spec wording for MTUExceeded says the reject\nidentifier shall match the first request command in the packet, and\nthat packets containing only responses shall be silently discarded.\nLinux intentionally deviates from that prescription: silently\ndiscarding desynchronizes the peer because the remote stack never\nlearns its responses were dropped, and locating the first request\ncommand requires walking command headers past MTUsig, i.e. processing\nbytes from a packet we have already decided is too large to process.\nWe therefore always emit one reject and use the identifier from the\nfirst command header, a single fixed-offset byte read.\n\nThe unrestricted BR/EDR signaling parser and ECHO_REQ response path both\ntrace to the initial git import; no later introducing commit is\navailable for a Fixes tag.","Type":"Description","Title":"Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig"}]}}}