{"id":"CVE-2026-53254","state":"PUBLISHED","title":"Bluetooth: RFCOMM: validate skb length in MCC handlers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: validate skb length in MCC handlers\n\nThe RFCOMM MCC handlers cast skb->data to protocol-specific structs\nwithout validating skb->len first. A malicious remote device can send\ntruncated MCC frames and trigger out-of-bounds reads in these handlers.\n\nFix this by using skb_pull_data() to validate and access the required\ndata before dereferencing it.\n\nrfcomm_recv_rpn() requires special handling since ETSI TS 07.10 allows\n1-byte RPN requests. Handle this by validating only the DLCI byte first,\nand validating the full struct only when len > 1.","publishedAt":"2026-06-25T08:39:45.273Z","updatedAt":"2026-10-19T19:57:31.915Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"7c15c7c2878957cbfed93bcc29c13fdace464254","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"0d637136ce89f9a2309b2c3502402ce400dab0ef","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"98377e6b1a1a56561ec66a181573ea2b61b2079e","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"1b070ac9e99c2c2c3a8112943ca98ab6fca7f10c","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"3eabc6d47a0ad22b053329997aaf0ec1e581e392","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"08b9c1fbe78f4ad3f6250c6541cfaabdbeb81997","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"23882b828c3c8c51d0c946446a396b10abb3b16b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/core.c"]}],"references":["https://git.kernel.org/stable/c/7c15c7c2878957cbfed93bcc29c13fdace464254","https://git.kernel.org/stable/c/0d637136ce89f9a2309b2c3502402ce400dab0ef","https://git.kernel.org/stable/c/98377e6b1a1a56561ec66a181573ea2b61b2079e","https://git.kernel.org/stable/c/1b070ac9e99c2c2c3a8112943ca98ab6fca7f10c","https://git.kernel.org/stable/c/3eabc6d47a0ad22b053329997aaf0ec1e581e392","https://git.kernel.org/stable/c/08b9c1fbe78f4ad3f6250c6541cfaabdbeb81997","https://git.kernel.org/stable/c/23882b828c3c8c51d0c946446a396b10abb3b16b","https://cert-portal.siemens.com/productcert/html/ssa-784472.html"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:16.098Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/53xxx/CVE-2026-53254.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-53254","state":"PUBLISHED","datePublished":"2026-06-25T08:39:45.273Z","dateUpdated":"2026-10-19T19:57:31.915Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-06-09T07:44:35.394Z"},"containers":{"cna":{"title":"Bluetooth: RFCOMM: validate skb length in MCC handlers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: validate skb length in MCC handlers\n\nThe RFCOMM MCC handlers cast skb->data to protocol-specific structs\nwithout validating skb->len first. A malicious remote device can send\ntruncated MCC frames and trigger out-of-bounds reads in these handlers.\n\nFix this by using skb_pull_data() to validate and access the required\ndata before dereferencing it.\n\nrfcomm_recv_rpn() requires special handling since ETSI TS 07.10 allows\n1-byte RPN requests. Handle this by validating only the DLCI byte first,\nand validating the full struct only when len > 1."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"7c15c7c2878957cbfed93bcc29c13fdace464254","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"0d637136ce89f9a2309b2c3502402ce400dab0ef","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"98377e6b1a1a56561ec66a181573ea2b61b2079e","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"1b070ac9e99c2c2c3a8112943ca98ab6fca7f10c","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"3eabc6d47a0ad22b053329997aaf0ec1e581e392","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"08b9c1fbe78f4ad3f6250c6541cfaabdbeb81997","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"23882b828c3c8c51d0c946446a396b10abb3b16b","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.15.210","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.176","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.143","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.94","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.36","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.13","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/rfcomm/core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7c15c7c2878957cbfed93bcc29c13fdace464254"},{"url":"https://git.kernel.org/stable/c/0d637136ce89f9a2309b2c3502402ce400dab0ef"},{"url":"https://git.kernel.org/stable/c/98377e6b1a1a56561ec66a181573ea2b61b2079e"},{"url":"https://git.kernel.org/stable/c/1b070ac9e99c2c2c3a8112943ca98ab6fca7f10c"},{"url":"https://git.kernel.org/stable/c/3eabc6d47a0ad22b053329997aaf0ec1e581e392"},{"url":"https://git.kernel.org/stable/c/08b9c1fbe78f4ad3f6250c6541cfaabdbeb81997"},{"url":"https://git.kernel.org/stable/c/23882b828c3c8c51d0c946446a396b10abb3b16b"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","baseScore":8.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:A - An attacker reaches the vulnerable RFCOMM MCC parsing code by sending malformed Bluetooth RFCOMM frames over a BR/EDR L2CAP connection. Bluetooth requires radio adjacency rather than ordinary IP network reachability.\nAC:L - The attacker controls the RFCOMM frame contents and can send truncated MCC frames directly after establishing the Bluetooth/L2CAP connection. No race or condition outside the attacker’s control is required.\nPR:N - The RFCOMM L2CAP listener uses the SDP/low-security path, and the vulnerable control-channel parsing occurs before RFCOMM DLC/service-level authentication. A malicious nearby Bluetooth device does not need local privileges or authenticated credentials.\nUI:N - No victim action is needed once the target Bluetooth stack is reachable and accepting RFCOMM/L2CAP traffic. The attacker sends the malformed frames directly.\nS:U - The impact is within the Linux kernel Bluetooth/RFCOMM security authority. There is no VM escape, IOMMU bypass, or separate security scope crossed.\nC:H - The bug is an out-of-bounds read from kernel skb memory, and some handler paths can reflect values derived from parsed control fields back to the peer. Under the required higher-severity rule, this is scored as high confidentiality impact.\nI:N - The fix and code review show bounded out-of-bounds reads, not an out-of-bounds write, use-after-free, or control-flow corruption primitive. Any state changes are limited to RFCOMM negotiation for the attacker-controlled connection.\nA:H - Malformed short Bluetooth frames can trigger kernel out-of-bounds reads in the RFCOMM receive thread, with related Bluetooth short-frame bugs producing KASAN slab-out-of-bounds reports. Under kernel scoring guidance, such remotely triggerable kernel fault conditions are high availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:34:35.807Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.210"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.94"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.36"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.0.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"affected":[{"vendor":"Siemens","product":"SIMATIC S7-1500 TM MFP - GNU/Linux subsystem","defaultStatus":"unknown","versions":[{"version":"0","status":"affected","lessThan":"*","versionType":"custom"}]}],"references":[{"url":"https://cert-portal.siemens.com/productcert/html/ssa-784472.html"}],"providerMetadata":{"shortName":"siemens-SADP","orgId":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e","dateUpdated":"2026-10-15T01:23:01.594Z"},"x_adpType":"supplier"},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-53254","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:27:49.303363Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:57:31.915Z"}}]}}}