tpm: Make the TPM character devices non-seekable

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72135
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:30 UTC
Updated2026-08-15 06:21:30 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.002200000 probability, percentile 0.127340000 (date 2026-08-15)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 ed0ffc2c016629e40ba041ed0424a772d8b02e2c git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 232dcf908eb7eb9d8046a9597975caf44270966e git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 dda695fab5e21f923d29e8cb01df256468ddfbd1 git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 9c513dabd4540f811585a2087f23069767a284da git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 21a13f932972bc9836f58c44fcd47c62abdecd95 git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 ada4b9a5087ea7f30dd8e4c6411a4fb6547eb1ed git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 947b773caaa548672184df025271b29bdc80b0f1 git Not specified
CNA Linux Linux affected 9488585b21bef0df1217e510c7134905d1d376a7 f20d61c22bcaf172d6790b6500e3838e532e71c8 git Not specified
CNA Linux Linux affected 5.0 Not specified
CNA Linux Linux unaffected 5.0 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/dda695fab5e21f923d29e8cb01df256468ddfbd1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f20d61c22bcaf172d6790b6500e3838e532e71c8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/21a13f932972bc9836f58c44fcd47c62abdecd95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/947b773caaa548672184df025271b29bdc80b0f1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ada4b9a5087ea7f30dd8e4c6411a4fb6547eb1ed 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ed0ffc2c016629e40ba041ed0424a772d8b02e2c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/232dcf908eb7eb9d8046a9597975caf44270966e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9c513dabd4540f811585a2087f23069767a284da 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report