Swtpm: swtpm: out-of-bounds read in swtpm_nvram_checkheader due to sizeof(pointer) vs sizeof(struct) mismatch
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · High
- Fix status
- Deferred Red Hat: fix deferred
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 8 | — | — | No fix listed | CNA |
| Red Hat | Red Hat Enterprise Linux 9 | — | — | No fix listed | CNA |
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-75900
- 2026-10-03 Alias added: GHSA-gqrg-h59c-j4wj
References
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Sources
- CVE-2026-75900 · CVE Program
- CVE-2026-75900 · NVD
- FIRST EPSS
- GHSA-gqrg-h59c-j4wj · GitHub Advisory Database · CC BY 4.0
- CVE-2026-75900 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences