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.

A flaw was found in the Linux kernel's IPv4 networking component. This vulnerability allows an unprivileged application to set specific IP options, namely Loose Source and Record Route (LSRR) and Strict Source and Record Route (SSRR). By exploiting this, an attacker can force network packets to traverse through attacker-controlled nodes, leading to the leakage of sensitive information such as TCP Initial Sequence Numbers (ISN) and potentially other protocol details.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Affected kernel Red Hat Enterprise Linux 7 Affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-53249 https://nvd.nist.gov/vuln/detail/CVE-2026-53249 https://lore.kernel.org/linux-cve-announce/2026062513-CVE-2026-53249-0107@gregkh/T