Medium [CVE-2026-75900] Out-of-bounds read in SWTPM_NVRAM_CheckHeader due to sizeof(pointer) vs sizeof(struct) mismatch
This medium-severity Red Hat Linux advisory covers CVE-2026-75900 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.
Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.
VulniPulse record published Record updated
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
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.
Red Hat rates this issue as Moderate impact. An attacker with access to the control channel can send an 8-byte state blob that passes this guard; the subsequent read of bh->totlen at offset 6 overreads the heap allocation by 2 bytes.
The out-of-bounds value is then printed to the swtpm log, leaking a small amount of adjacent heap data. This is distinct from CVE-2022-23645, which added validation on the hdrsize field below this guard but did not fix the entry length check.
Red Hat severity: Moderate — CVSS 6.1 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H). Weakness: CWE-125.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: swtpm.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 18 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 18 days ago·verify at source
Mitigation checklist
- Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Fixed version: 0.10.2
Official advisory · high-confidence parse· fetched 18 days ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.