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CVE-2026-53249

Updated on 25 Jun 2026

Severity

5.5 Medium severity

Details

CVSS score
5.5
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

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.

Details

Affected product:
AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
Affected packages:
kernel @ 4.18.0 (+17 more)

Fixes

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Amazon Linux 2023 Planned —
Debian 11 Planned —
Debian 11 cloud Planned —
Debian 12 In Rollout
40 kernels
  • 6.1.38-1
  • 6.1.38-2
  • 6.1.38-4
  • 6.1.52-1
  • 6.1.55-1
  • 6.1.64-1
  • 6.1.66-1
  • 6.1.69-1
  • 6.1.76-1
  • 6.1.27-1
  • 6.1.67-1
  • 6.1.85-1
  • 6.1.90-1
  • 6.1.94-1
  • 6.1.99-1
  • 6.1.106-3
  • 6.1.112-1
  • 6.1.115-1
  • 6.1.119-1
  • 6.1.123-1
  • 6.1.128-1
  • 6.1.124-1
  • 6.1.129-1
  • 6.1.133-1
  • 6.1.135-1
  • 6.1.137-1
  • 6.1.140-1
  • 6.1.139-1
  • 6.1.147-1
  • 6.1.148-1
  • 6.1.153-1
  • 6.1.158-1
  • 6.1.159-1
  • 6.1.162-1
  • 6.1.164-1
  • 6.1.170-1
  • 6.1.170-3
  • 6.1.172-1
  • 6.1.174-1
  • 6.1.170-2