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tpm: Make the TPM character devices non-seekable

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: tpm: Make the TPM character devices non-seekable The TPM character devices expose a sequential command/response interface, but their open handlers leave FMODE_PREAD and FMODE_PWRITE enabled. After a command leaves a response pending, pread(fd, buf, 16, 0x1400) passes 0x1400 as *off to tpm_common_read(). The transfer length is bounded by response_length, but the offset is used unchecked when forming data_buffer + *off. A sufficiently large offset therefore causes an out-of-bounds heap read through copy_to_user() and, if the copy succeeds, an out-of-bounds zero-write through the following memset(). Positional I/O does not provide coherent semantics for this interface. An arbitrary pread offset cannot represent how much of a response has been consumed sequentially. The write callback always stores a command at the start of data_buffer, while pwrite() does not update file->f_pos and can leave the sequential read cursor stale. Call nonseekable_open() from both open handlers. This removes FMODE_PREAD and FMODE_PWRITE, causing positional reads and writes to fail with -ESPIPE before reaching the TPM callbacks, and explicitly marks the files non-seekable. Normal read() and write() continue to use the existing sequential f_pos cursor, leaving the response state machine unchanged. Tested on Linux 6.12 with KASAN and a swtpm TPM2 device: - sequential partial reads returned the complete response - pread() and preadv() wit

Announced Source revision 1
Original source ↗

CVE-2026-72135

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-72135

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "ed0ffc2c016629e40ba041ed0424a772d8b02e2c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "232dcf908eb7eb9d8046a9597975caf44270966e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "dda695fab5e21f923d29e8cb01df256468ddfbd1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "9c513dabd4540f811585a2087f23069767a284da",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "21a13f932972bc9836f58c44fcd47c62abdecd95",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "ada4b9a5087ea7f30dd8e4c6411a4fb6547eb1ed",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "947b773caaa548672184df025271b29bdc80b0f1",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9488585b21bef0df1217e510c7134905d1d376a7",
        "lessThan": "f20d61c22bcaf172d6790b6500e3838e532e71c8",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/char/tpm/tpm-dev.c",
      "drivers/char/tpm/tpmrm-dev.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.261",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.212",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/char/tpm/tpm-dev.c",
      "drivers/char/tpm/tpmrm-dev.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72135

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#32954 · Revision 1
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Publisher date
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