Use of Out-of-range Pointer Offset Affecting kernel-tools-libs-devel package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.16% (7th percentile)

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  • Snyk IDSNYK-RHEL10-KERNELTOOLSLIBSDEVEL-18897950
  • published18 Aug 2026
  • disclosed15 Aug 2026

Introduced: 15 Aug 2026

NewCVE-2026-72135  (opens in a new tab)
CWE-823  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 kernel-tools-libs-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-tools-libs-devel package and not the kernel-tools-libs-devel package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

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() with offset 0x1400 returned -ESPIPE
  • pwrite() and pwritev() with offset zero returned -ESPIPE
  • the pending response remained intact after the rejected operations
  • a subsequent normal command/response cycle completed normally
  • no KASAN report was produced.

CVSS Base Scores

version 3.1