# CVE-2026-43495: net: wwan: t7xx: validate port_count against message length in t7xx_port_enum_msg_handler

> A malicious modem can trigger a slab-out-of-bounds read in the Linux kernel t7xx WWAN driver, potentially causing a crash or leaking memory.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43495, DEBIAN-CVE-2026-43495, GHSA-mhw6-p52x-6vxv, ROOT-OS-DEBIAN-12-CVE-2026-43495, ROOT-OS-UBUNTU-2404-CVE-2026-43495, UBUNTU-CVE-2026-43495

## What is CVE-2026-43495?

CVE-2026-43495 is a high-severity memory corruption vulnerability in Linux kernel, published on 21 May 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:

net: wwan: t7xx: validate port_count against message length in t7xx_port_enum_msg_handler

t7xx_port_enum_msg_handler() uses the modem-supplied port_count field as
a loop bound over port_msg->data[] without checking that the message buffer
contains sufficient data. A modem sending port_count=65535 in a 12-byte
buffer triggers a slab-out-of-bounds read of up to 262140 bytes.

Add a sizeof(*port_msg) check before accessing the port message header
fields to guard against undersized messages.

Add a struct_size() check after extracting port_count and before the loop.

In t7xx_parse_host_rt_data(), guard the rt_feature header read with a
remaining-buffer check before accessing data_len, validate feat_data_len
against the actual remaining buffer to prevent OOB reads and signed
integer overflow on offset.

Pass msg_len from both call sites: skb->len at the DPMAIF path after
skb_pull(), and the validated feat_data_len at the handshake path.

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

## Which versions are affected by CVE-2026-43495?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43495?

Apply the vendor's patch.

## Is CVE-2026-43495 being exploited?

There is no known exploitation of CVE-2026-43495 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-2026-43495 and fix it if it is affected.

What it is: CVE-2026-43495 is a high-severity memory corruption vulnerability in Linux kernel, published on 21 May 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-2026-43495 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-2026-43495/ (Markdown: https://insights.sbomify.com/CVE-2026-43495/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43495
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43495
- OSV: https://osv.dev/vulnerability/CVE-2026-43495

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43495/
Summaries are generated and may contain mistakes; the official description above is the record.