CVE-2026-53078 bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops
A flaw in Linux kernel BPF sock_ops allows attackers to leak kernel pointers or cause out-of-bounds reads via specific register usage.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-53078?
CVE-2026-53078 is a high-severity vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-125
Which versions are affected by CVE-2026-53078?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-53078?
Apply the vendor's patch.
Is CVE-2026-53078 being exploited?
There is no known exploitation of CVE-2026-53078 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90669, BELL-CVE-2026-53078, DEBIAN-CVE-2026-53078, GHSA-pwr6-cvf5-35f3, ROOT-OS-DEBIAN-11-CVE-2026-53078, ROOT-OS-DEBIAN-12-CVE-2026-53078 and 4 more.