# CVE-2022-48839: net/packet: fix slab-out-of-bounds access in packet_recvmsg()

> A local attacker can trigger a slab-out-of-bounds read in the Linux kernel's packet socket implementation, potentially leaking memory or causing a crash.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 16 Jul 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-48839, GHSA-qvwc-r3r6-hq25, UBUNTU-CVE-2022-48839

## What is CVE-2022-48839?

CVE-2022-48839 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Jul 2024. 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:

net/packet: fix slab-out-of-bounds access in packet_recvmsg()

syzbot found that when an AF_PACKET socket is using PACKET_COPY_THRESH
and mmap operations, tpacket_rcv() is queueing skbs with
garbage in skb->cb[], triggering a too big copy [1]

Presumably, users of af_packet using mmap() already gets correct
metadata from the mapped buffer, we can simply make sure
to clear 12 bytes that might be copied to user space later.

BUG: KASAN: stack-out-of-bounds in memcpy include/linux/fortify-string.h:225 [inline]
BUG: KASAN: stack-out-of-bounds in packet_recvmsg+0x56c/0x1150 net/packet/af_packet.c:3489
Write of size 165 at addr ffffc9000385fb78 by task syz-executor233/3631

CPU: 0 PID: 3631 Comm: syz-executor233 Not tainted 5.17.0-rc7-syzkaller-02396-g0b3660695e80 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0xf/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 memcpy+0x39/0x60 mm/kasan/shadow.c:66
 memcpy include/linux/fortify-string.h:225 [inline]
 packet_recvmsg+0x56c/0x1150 net/packet/af_packet.c:3489
 sock_recvmsg_nosec net/socket.c:948 [inline]
 sock_recvmsg net/socket.c:966 [inline]
 sock_recvmsg net/socket.c:962 [inline]
 ____sys_recvmsg+0x2c4/0x600 net/socket.c:2632
 ___sys_recvmsg+0x127/0x200 net/socket.c:2674
 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2704
 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
RIP: 0033:0x7fdfd5954c29
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 15 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcf8e71e48 EFLAGS: 00000246 ORIG_RAX: 000000000000002f
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fdfd5954c29
RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000005
RBP: 0000000000000000 R08: 000000000000000d R09: 000000000000000d
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcf8e71e60
R13: 00000000000f4240 R14: 000000000000c1ff R15: 00007ffcf8e71e54
 </TASK>

addr ffffc9000385fb78 is located in stack of task syz-executor233/3631 at offset 32 in frame:
 ____sys_recvmsg+0x0/0x600 include/linux/uio.h:246

this frame has 1 object:
 [32, 160) 'addr'

Memory state around the buggy address:
 ffffc9000385fa80: 00 04 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00
 ffffc9000385fb00: 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00
>ffffc9000385fb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f3
                                                                ^
 ffffc9000385fc00: f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 f1
 ffffc9000385fc80: f1 f1 f1 00 f2 f2 f2 00 f2 f2 f2 00 00 00 00 00
==================================================================

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2022-48839?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48839?

Apply the vendor's patch.

## Is CVE-2022-48839 being exploited?

There is no known exploitation of CVE-2022-48839 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-48839 and fix it if it is affected.

What it is: CVE-2022-48839 is a high-severity memory corruption vulnerability in Linux kernel, published on 16 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-48839 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-48839/ (Markdown: https://insights.sbomify.com/CVE-2022-48839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48839
- OSV: https://osv.dev/vulnerability/CVE-2022-48839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48839/
Summaries are generated and may contain mistakes; the official description above is the record.