# CVE-2026-53078

## Summary

- **CVE ID:** CVE-2026-53078
- **Severity:** HIGH
- **CVSS Score:** 7.8 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **CWE:** N/A
- **Published:** Jun 24, 2026
- **Last Modified:** Sep 14, 2026

## 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.

## Affected Products

- Linux — Linux (fd09af010788a884de1c39537c288830c3d305db)
- Linux — Linux (48be3df15aa19c04eadf156c9129293c9a10389f)
- Linux — Linux (cd4644d904e1d153d516e73e2e127e7a2fe687e1)
- Linux — Linux (6e0bc946cbeec538322820786b5fb5200a2216ab)
- Linux — Linux (a7e52f7f675046d9ffc5692d815fa67c82fcdbf5)
- Linux — Linux (db7f8c57dbdd31f7e59f8dc8d1e1b38607a320ef)
- Linux — Linux (5.7.18)
- Linux — Linux (5.8.4)
- Linux — Linux (5.4.61)
- Linux — Linux (5.9)
- Linux — Linux (0)
- Linux — Linux (7.0.10)
- Linux — Linux (7.1)
- Linux — Linux (6.12.101)
- Linux — Linux (6.18.42)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/18e3ffde1822f0b48b1753bf34aa97ce839df1d8)
- [CNA](https://git.kernel.org/stable/c/10f86a2a5c91fc4c4d001960f1c21abe52545ef6)
- [CNA](https://git.kernel.org/stable/c/2a2c98141e0a75f2d4a7d78b0316c88b3da784ac)
- [CNA](https://git.kernel.org/stable/c/22400725de070b787cd6d806c5795370ab46d269)
- [CNA](https://git.kernel.org/stable/c/db1200ec2c3ddf119d4d9ba67982063df06bbacb)
- [CNA](https://git.kernel.org/stable/c/4c1c5efd9d1d74743d41ce4e1600501b4feb6827)
- [CNA](https://git.kernel.org/stable/c/0e6b30657bbc771f38025c828d722b6162428508)
- [CNA](https://git.kernel.org/stable/c/64eaf4ecda007140ddcdb28e00c48c9c69aaba39)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.12%
- **EPSS Percentile:** 2.1

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._