Out-of-bounds read in Linux kernel - CVE-2026-52910

Vulnerability details

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to an out-of-bounds read in the reuseport cBPF program handling in sk_reuseport_prog_free() when detaching or replacing a reuseport program while UDP packets are being processed concurrently. A local user can trigger concurrent reuseport program updates and packet transmission to cause a denial of service.

The issue occurs because the classic BPF reuseport program may be freed before RCU readers have completed.

Affected software

How to mitigate CVE-2026-52910

External References

• https://git.kernel.org/stable/c/08264d5bba0bdd3a79bc2984fee09286aba0c4eb
• https://git.kernel.org/stable/c/18fc650ccd7fe3376eca89203668cfb8268f60df
• https://git.kernel.org/stable/c/298db6167f81e9c470a57cf652e4e47757b4293e
• https://git.kernel.org/stable/c/87dfb977bdb6eaa47e9993a34e18f44970f88b1f
• https://git.kernel.org/stable/c/90e47dc5c572d1c73971ac51c7428803f42b78eb
• https://git.kernel.org/stable/c/c3e3fddda6b5d9ba505d218b4055e7d8a282ac57
• https://git.kernel.org/stable/c/f8b8f1d4bb76098e87b8269a0631019648330e6d
• https://git.kernel.org/stable/c/fec41484e7c2aa7ded44c541bba98872be937754

Related Security Bulletins

• Out-of-bounds read in Linux kernel core
• Debian update for linux