# CVE-2023-53026: RDMA/core: Fix ib block iterator counter overflow

> An integer overflow in the Linux kernel RDMA core allows a local attacker to cause an infinite loop and system denial of service.

- **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:** 27 Mar 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-53026, DEBIAN-CVE-2023-53026, GHSA-gr26-qx48-q4hh, UBUNTU-CVE-2023-53026

## What is CVE-2023-53026?

CVE-2023-53026 is a high-severity vulnerability in Linux kernel, published on 27 Mar 2025. 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/core: Fix ib block iterator counter overflow

When registering a new DMA MR after selecting the best aligned page size
for it, we iterate over the given sglist to split each entry to smaller,
aligned to the selected page size, DMA blocks.

In given circumstances where the sg entry and page size fit certain
sizes and the sg entry is not aligned to the selected page size, the
total size of the aligned pages we need to cover the sg entry is >= 4GB.
Under this circumstances, while iterating page aligned blocks, the
counter responsible for counting how much we advanced from the start of
the sg entry is overflowed because its type is u32 and we pass 4GB in
size. This can lead to an infinite loop inside the iterator function
because the overflow prevents the counter to be larger
than the size of the sg entry.

Fix the presented problem by changing the advancement condition to
eliminate overflow.

Backtrace:
[  192.374329] efa_reg_user_mr_dmabuf
[  192.376783] efa_register_mr
[  192.382579] pgsz_bitmap 0xfffff000 rounddown 0x80000000
[  192.386423] pg_sz [0x80000000] umem_length[0xc0000000]
[  192.392657] start 0x0 length 0xc0000000 params.page_shift 31 params.page_num 3
[  192.399559] hp_cnt[3], pages_in_hp[524288]
[  192.403690] umem->sgt_append.sgt.nents[1]
[  192.407905] number entries: [1], pg_bit: [31]
[  192.411397] biter->__sg_nents [1] biter->__sg [0000000008b0c5d8]
[  192.415601] biter->__sg_advance [665837568] sg_dma_len[3221225472]
[  192.419823] biter->__sg_nents [1] biter->__sg [0000000008b0c5d8]
[  192.423976] biter->__sg_advance [2813321216] sg_dma_len[3221225472]
[  192.428243] biter->__sg_nents [1] biter->__sg [0000000008b0c5d8]
[  192.432397] biter->__sg_advance [665837568] sg_dma_len[3221225472]

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2023-53026?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53026?

Apply the vendor's patch.

## Is CVE-2023-53026 being exploited?

There is no known exploitation of CVE-2023-53026 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-2023-53026 and fix it if it is affected.

What it is: CVE-2023-53026 is a high-severity vulnerability in Linux kernel, published on 27 Mar 2025. 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-2023-53026 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-2023-53026/ (Markdown: https://insights.sbomify.com/CVE-2023-53026/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53026
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53026
- OSV: https://osv.dev/vulnerability/CVE-2023-53026

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53026/
Summaries are generated and may contain mistakes; the official description above is the record.