Bug 2555107 (CVE-2026-98728) - CVE-2026-98728 kernel: tpm: fix off-by-four bounds check in tpm2_get_random()
Summary: CVE-2026-98728 kernel: tpm: fix off-by-four bounds check in tpm2_get_random()
Keywords:
Status: NEW
Alias: CVE-2026-98728
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-18 15:54 UTC by OSIDB Bzimport
Modified: 2026-10-22 23:45 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2026-10-18 15:54:49 UTC
In the Linux kernel, the following vulnerability has been resolved:

tpm: fix off-by-four bounds check in tpm2_get_random()

When the response carries the TPM2_ST_SESSIONS tag, tpm2_get_random()
skips the 4-byte parameter size field before locating the random data,
but the bounds check still validates the response length against
TPM_HEADER_SIZE.  A truncated response can pass the check and make
memcpy() read up to 4 bytes past the response end, so stale buffer
contents end up in the caller's random bytes.

Fix this by checking the response length against 'offset', which
already includes the skipped parameter size field.


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