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6.1 Medium

CVE-2026-75900 Swtpm: swtpm: out-of-bounds read in swtpm_nvram_checkheader due to sizeof(pointer) vs sizeof(struct) mismatch

Description

An out-of-bounds read vulnerability was found in swtpm's SWTPM_NVRAM_CheckHeader() function. The entry guard checks the buffer length against sizeof(bh), where bh is a pointer, instead of sizeof(*bh), the actual struct size. This allows an undersized buffer to pass validation, causing a 2-byte heap overread on 64-bit systems (6 bytes on 32-bit) when accessing the totlen field. This may cause daemon termination on some platforms and leaks heap data to the log.

CVSS 3.1 detail

Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H

Exploitable with local access to the machine, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High

Affected products and versions

Product Affected versions Fixed in
Red Hat Enterprise Linux 10 Versions not published
Red Hat Enterprise Linux 8 Versions not published
Red Hat Enterprise Linux 9 Versions not published
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