{"id":"CVE-2026-72135","revision":"f47f04a2310343d781386ee7888029df","records":[{"revision":"f47f04a2310343d781386ee7888029df","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72135","aliases":[],"title":"tpm: Make the TPM character devices non-seekable","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntpm: Make the TPM character devices non-seekable\n\nThe TPM character devices expose a sequential command/response\ninterface, but their open handlers leave FMODE_PREAD and FMODE_PWRITE\nenabled.\n\nAfter a command leaves a response pending, pread(fd, buf, 16, 0x1400)\npasses 0x1400 as *off to tpm_common_read(). The transfer length is\nbounded by response_length, but the offset is used unchecked when\nforming data_buffer + *off. A sufficiently large offset therefore causes\nan out-of-bounds heap read through copy_to_user() and, if the copy\nsucceeds, an out-of-bounds zero-write through the following memset().\n\nPositional I/O does not provide coherent semantics for this interface.\nAn arbitrary pread offset cannot represent how much of a response has\nbeen consumed sequentially. The write callback always stores a command\nat the start of data_buffer, while pwrite() does not update file->f_pos\nand can leave the sequential read cursor stale.\n\nCall nonseekable_open() from both open handlers. This removes\nFMODE_PREAD and FMODE_PWRITE, causing positional reads and writes to\nfail with -ESPIPE before reaching the TPM callbacks, and explicitly\nmarks the files non-seekable. Normal read() and write() continue to use\nthe existing sequential f_pos cursor, leaving the response state machine\nunchanged.\n\nTested on Linux 6.12 with KASAN and a swtpm TPM2 device:\n\n - sequential partial reads returned the complete response\n - pread() and preadv() with offset 0x1400 returned -ESPIPE\n - pwrite() and pwritev() with offset zero returned -ESPIPE\n - the pending response remained intact after the rejected operations\n - a subsequent normal command/response cycle completed normally\n - no KASAN report was produced.","state":0,"publishedAt":"2026-08-15T05:53:10.315+00:00","modifiedAt":"2026-10-16T18:44:58.643+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/char/tpm/tpm-dev.c\",\n                        \"drivers/char/tpm/tpmrm-dev.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"ed0ffc2c016629e40ba041ed0424a772d8b02e2c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"232dcf908eb7eb9d8046a9597975caf44270966e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"dda695fab5e21f923d29e8cb01df256468ddfbd1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"9c513dabd4540f811585a2087f23069767a284da\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"21a13f932972bc9836f58c44fcd47c62abdecd95\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"ada4b9a5087ea7f30dd8e4c6411a4fb6547eb1ed\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"947b773caaa548672184df025271b29bdc80b0f1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9488585b21bef0df1217e510c7134905d1d376a7\",\n                            \"lessThan\": \"f20d61c22bcaf172d6790b6500e3838e532e71c8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/char/tpm/tpm-dev.c\",\n                        \"drivers/char/tpm/tpmrm-dev.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.0\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.0\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.261\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.212\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.178\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.97\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.40\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.5\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/ed0ffc2c016629e40ba041ed0424a772d8b02e2c","https://git.kernel.org/stable/c/232dcf908eb7eb9d8046a9597975caf44270966e","https://git.kernel.org/stable/c/dda695fab5e21f923d29e8cb01df256468ddfbd1","https://git.kernel.org/stable/c/9c513dabd4540f811585a2087f23069767a284da","https://git.kernel.org/stable/c/21a13f932972bc9836f58c44fcd47c62abdecd95","https://git.kernel.org/stable/c/ada4b9a5087ea7f30dd8e4c6411a4fb6547eb1ed","https://git.kernel.org/stable/c/947b773caaa548672184df025271b29bdc80b0f1","https://git.kernel.org/stable/c/f20d61c22bcaf172d6790b6500e3838e532e71c8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72135","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72135","identifiers":["CVE-2026-72135"]},"retained":false,"historicalAffected":[]}],"coverage":[]}