CVE-2022-49228

What it is

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a btf decl_tag bug when tagging a function syzbot reported a btf decl_tag bug with stack trace below: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 3592 Comm: syz-executor914 Not tainted 5.16.0-syzkaller-11424-gb7892f7d5cb2 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:btf_type_vlen include/linux/btf.h:231 [inline] RIP: 0010:btf_decl_tag_resolve+0x83e/0xaa0 kernel/bpf/btf.c:3910 ... Call Trace: <TASK> btf_resolve+0x251/0x1020 kernel/bpf/btf.c:4198 btf_check_all_types kernel/bpf/btf.c:4239 [inline] btf_parse_type_sec kernel/bpf/btf.c:4280 [inline] btf_parse kernel/bpf/btf.c:4513 [inline] btf_new_fd+0x19fe/0x2370 kernel/bpf/btf.c:6047 bpf_btf_load kernel/bpf/syscall.c:4039 [inline] __sys_bpf+0x1cbb/0x5970 kernel/bpf/syscall.c:4679 __do_sys_bpf kernel/bpf/syscall.c:4738 [inline] __se_sys_bpf kernel/bpf/syscall.c:4736 [inline] __x64_sys_bpf+0x75/0xb0 kernel/bpf/syscall.c:4736 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae The kasan error is triggered with an illegal BTF like below: type 0: void type 1: int type 2: decl_tag to func type 3 type 3: func to func_proto type 8 The total number of types is 4 and the type 3 is illegal since its func_proto type is out of range. Currently, the target type of decl_tag can be struct/union, var or func. Both struct/union and var implemented their own 'resolve' callback functions and hence handled properly in kernel. But func type doesn't have 'resolve' callback function. When btf_decl_tag_resolve() tries to check func type, it tries to get vlen of its func_proto type, which triggered the above kasan error. To fix the issue, btf_decl_tag_resolve() needs to do btf_func_check() before trying to accessing func_proto type. In the current implementation, func type is checked with btf_func_check() in the main checking function btf_check_all_types(). To fix the above kasan issue, let us implement 'resolve' callback func type properly. The 'resolve' callback will be also called in btf_check_all_types() for func types.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-02-26 07:00 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 05:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 5.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2025-02-26 07:00 UTC

Last modified

2026-06-17 05:17 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-476 · NULL pointer dereference

Record status

Analyzed

Affected

• Linux Kernel < 5.16.19
• Linux Kernel < 5.17.2

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2022-49228.md and follow it. Check whether this project is affected by CVE-2022-49228. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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