PT-2026-52344 · Linux · Linux

Published 2026-06-25 · Updated 2026-06-25 · CVE-2026-53249

Mitre

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.

Related Identifiers

CVE-2026-53249

Affected Products

Linux

References · 9

• https://nvd.nist.gov/vuln/detail/CVE-2026-53249 · Security Note
• https://git.kernel.org/stable/c/89343ff12b3178fc236fe531a3603e7c97c68278 · Note
• https://git.kernel.org/stable/c/4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2 · Note
• https://git.kernel.org/stable/c/00e8845fe3428c69e980dce5071cb3da1d8f7578 · Note
• https://git.kernel.org/stable/c/2a87c3e8f03ce655ed0ef500d64d5fd924ec3691 · Note
• https://git.kernel.org/stable/c/28f5ad1b4055405eb1616e603fe511ba5e3725e7 · Note
• https://git.kernel.org/stable/c/d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c · Note
• https://git.kernel.org/stable/c/8ff85dbabbbfb05e86e6cde31d91ac5782179d4d · Note
• https://git.kernel.org/stable/c/a4f3fd6516920988c47ba8d19714985c40c816a1 · Note