# CVE-2026-53133: RDMA/umem: Fix truncation for block sizes >= 4G

> An integer overflow in the Linux kernel RDMA subsystem allows attackers to compute incorrect DMA addresses, potentially leading to memory corruption or privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 25 Jun 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-90962, BELL-CVE-2026-53133, DEBIAN-CVE-2026-53133, GHSA-5rwx-cqg3-893x, ROOT-OS-DEBIAN-11-CVE-2026-53133, ROOT-OS-DEBIAN-12-CVE-2026-53133, ROOT-OS-UBUNTU-2204-CVE-2026-53133, ROOT-OS-UBUNTU-2404-CVE-2026-53133, UBUNTU-CVE-2026-53133

## What is CVE-2026-53133?

CVE-2026-53133 is a high-severity vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

RDMA/umem: Fix truncation for block sizes >= 4G

When the iommu is used the linearization of the mapping can give a single
block that is very large split across multiple SG entries.

When __rdma_block_iter_next() reassembles the split SG entries it is
overflowing the 32 bit stack values and computed the wrong DMA addresses
for blocks after the truncation.

Use the right types to hold DMA addresses.

Weakness: CWE-681 (Incorrect Conversion between Numeric Types), CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-53133?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53133?

Apply the vendor's patch.

## Is CVE-2026-53133 being exploited?

There is no known exploitation of CVE-2026-53133 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53133 and fix it if it is affected.

What it is: CVE-2026-53133 is a high-severity vulnerability in Linux kernel, published on 25 Jun 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-2026-53133 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-53133/ (Markdown: https://insights.sbomify.com/CVE-2026-53133/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53133
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53133
- OSV: https://osv.dev/vulnerability/CVE-2026-53133

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53133/
Summaries are generated and may contain mistakes; the official description above is the record.