Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-06-24T00:00:00 kernel: bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-125

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops When a BPF sock_ops program accesses ctx fields with dst_reg == src_reg, the SOCK_OPS_GET_SK() and SOCK_OPS_GET_FIELD() macros fail to zero the destination register in the !fullsock / !locked_tcp_sock path. Both macros borrow a temporary register to check is_fullsock / is_locked_tcp_sock when dst_reg == src_reg, because dst_reg holds the ctx pointer. When the check is false (e.g., TCP_NEW_SYN_RECV state with a request_sock), dst_reg should be zeroed but is not, leaving the stale ctx pointer: - SOCK_OPS_GET_SK: dst_reg retains the ctx pointer, passes NULL checks as PTR_TO_SOCKET_OR_NULL, and can be used as a bogus socket pointer, leading to stack-out-of-bounds access in helpers like bpf_skc_to_tcp6_sock(). - SOCK_OPS_GET_FIELD: dst_reg retains the ctx pointer which the verifier believes is a SCALAR_VALUE, leaking a kernel pointer. Fix both macros by: - Changing JMP_A(1) to JMP_A(2) in the fullsock path to skip the added instruction. - Adding BPF_MOV64_IMM(si->dst_reg, 0) after the temp register restore in the !fullsock path, placed after the restore because dst_reg == src_reg means we need src_reg intact to read ctx->temp.

A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) socket operations (sock_ops) program. When a BPF sock_ops program accesses context fields with the same destination and source registers, certain macros fail to properly clear the destination register. This can lead to a stack-out-of-bounds access, potentially allowing an attacker to execute arbitrary code or cause a denial of service. Additionally, it can result in a kernel pointer leak, disclosing sensitive information.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not 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-2026-53078 https://nvd.nist.gov/vuln/detail/CVE-2026-53078 https://lore.kernel.org/linux-cve-announce/2026062406-CVE-2026-53078-bc4a@gregkh/T