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

> An out-of-bounds read in swtpm allows attackers to cause daemon termination and leak heap data via undersized buffers.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** AZL-96876, DEBIAN-CVE-2026-75900, GHSA-gqrg-h59c-j4wj, SUSE-SU-2026:23879-1, SUSE-SU-2026:23927-1, SUSE-SU-2026:24114-1, SUSE-SU-2026:24156-1, SUSE-SU-2026:4366-1, UBUNTU-CVE-2026-75900, openSUSE-SU-2026:11598-1, openSUSE-SU-2026:22048-1

## What is CVE-2026-75900?

CVE-2026-75900 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux 10, published on 19 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-75900?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `swtpm` | SUSE:Linux Enterprise Module for Server Applications 15 SP7 | All versions | 0.9.0-150700.3.3.1 |
| `swtpm` | SUSE:Linux Enterprise Server 16.0 | All versions | 0.10.2-160000.1.1 |
| `swtpm` | SUSE:Linux Enterprise Server for SAP applications 16.0 | All versions | 0.10.2-160000.1.1 |
| `swtpm` | SUSE:Linux Micro 6.0 | All versions | 0.8.0-2.1 |
| `swtpm` | SUSE:Linux Micro 6.1 | All versions | 0.9.0-slfo.1.1_3.1 |
| `swtpm` | SUSE:Linux Micro 6.2 | All versions | 0.10.2-160000.1.1 |
| `swtpm` | openSUSE:Leap 16.0 | All versions | 0.10.2-160000.1.1 |
| `swtpm` | openSUSE:Tumbleweed | All versions | 0.10.2-1.1 |

## How do I fix CVE-2026-75900?

Apply the vendor's patch.

## Is CVE-2026-75900 being exploited?

There is no known exploitation of CVE-2026-75900 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75900 and fix it if it is affected.

What it is: CVE-2026-75900 is a medium-severity memory corruption vulnerability in Red Hat Enterprise Linux 10, published on 19 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-75900 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-75900/ (Markdown: https://insights.sbomify.com/CVE-2026-75900/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75900
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75900
- OSV: https://osv.dev/vulnerability/CVE-2026-75900

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75900/
Summaries are generated and may contain mistakes; the official description above is the record.