# CVE-2022-50231: crypto: arm64/poly1305 - fix a read out-of-bound

> A read out-of-bounds vulnerability in the Linux kernel's ARM64 Poly1305 implementation allows attackers to cause crashes or leak memory.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/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:** 18 Jun 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-50231, GHSA-77mj-4rpp-qvxc, UBUNTU-CVE-2022-50231

## What is CVE-2022-50231?

CVE-2022-50231 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Jun 2025. 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:

crypto: arm64/poly1305 - fix a read out-of-bound

A kasan error was reported during fuzzing:

BUG: KASAN: slab-out-of-bounds in neon_poly1305_blocks.constprop.0+0x1b4/0x250 [poly1305_neon]
Read of size 4 at addr ffff0010e293f010 by task syz-executor.5/1646715
CPU: 4 PID: 1646715 Comm: syz-executor.5 Kdump: loaded Not tainted 5.10.0.aarch64 #1
Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.59 01/31/2019
Call trace:
 dump_backtrace+0x0/0x394
 show_stack+0x34/0x4c arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x158/0x1e4 lib/dump_stack.c:118
 print_address_description.constprop.0+0x68/0x204 mm/kasan/report.c:387
 __kasan_report+0xe0/0x140 mm/kasan/report.c:547
 kasan_report+0x44/0xe0 mm/kasan/report.c:564
 check_memory_region_inline mm/kasan/generic.c:187 [inline]
 __asan_load4+0x94/0xd0 mm/kasan/generic.c:252
 neon_poly1305_blocks.constprop.0+0x1b4/0x250 [poly1305_neon]
 neon_poly1305_do_update+0x6c/0x15c [poly1305_neon]
 neon_poly1305_update+0x9c/0x1c4 [poly1305_neon]
 crypto_shash_update crypto/shash.c:131 [inline]
 shash_finup_unaligned+0x84/0x15c crypto/shash.c:179
 crypto_shash_finup+0x8c/0x140 crypto/shash.c:193
 shash_digest_unaligned+0xb8/0xe4 crypto/shash.c:201
 crypto_shash_digest+0xa4/0xfc crypto/shash.c:217
 crypto_shash_tfm_digest+0xb4/0x150 crypto/shash.c:229
 essiv_skcipher_setkey+0x164/0x200 [essiv]
 crypto_skcipher_setkey+0xb0/0x160 crypto/skcipher.c:612
 skcipher_setkey+0x3c/0x50 crypto/algif_skcipher.c:305
 alg_setkey+0x114/0x2a0 crypto/af_alg.c:220
 alg_setsockopt+0x19c/0x210 crypto/af_alg.c:253
 __sys_setsockopt+0x190/0x2e0 net/socket.c:2123
 __do_sys_setsockopt net/socket.c:2134 [inline]
 __se_sys_setsockopt net/socket.c:2131 [inline]
 __arm64_sys_setsockopt+0x78/0x94 net/socket.c:2131
 __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline]
 invoke_syscall+0x64/0x100 arch/arm64/kernel/syscall.c:48
 el0_svc_common.constprop.0+0x220/0x230 arch/arm64/kernel/syscall.c:155
 do_el0_svc+0xb4/0xd4 arch/arm64/kernel/syscall.c:217
 el0_svc+0x24/0x3c arch/arm64/kernel/entry-common.c:353
 el0_sync_handler+0x160/0x164 arch/arm64/kernel/entry-common.c:369
 el0_sync+0x160/0x180 arch/arm64/kernel/entry.S:683

This error can be reproduced by the following code compiled as ko on a
system with kasan enabled:

#include <linux/module.h>
#include <linux/crypto.h>
#include <crypto/hash.h>
#include <crypto/poly1305.h>

char test_data[] = "\x00\x01\x02\x03\x04\x05\x06\x07"
                   "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
                   "\x10\x11\x12\x13\x14\x15\x16\x17"
                   "\x18\x19\x1a\x1b\x1c\x1d\x1e";

int init(void)
{
        struct crypto_shash *tfm = NULL;
        char *data = NULL, *out = NULL;

        tfm = crypto_alloc_shash("poly1305", 0, 0);
        data = kmalloc(POLY1305_KEY_SIZE - 1, GFP_KERNEL);
        out = kmalloc(POLY1305_DIGEST_SIZE, GFP_KERNEL);
        memcpy(data, test_data, POLY1305_KEY_SIZE - 1);
        crypto_shash_tfm_digest(tfm, data, POLY1305_KEY_SIZE - 1, out);

        kfree(data);
        kfree(out);
        return 0;
}

void deinit(void)
{
}

module_init(init)
module_exit(deinit)
MODULE_LICENSE("GPL");

The root cause of the bug sits in neon_poly1305_blocks. The logic
neon_poly1305_blocks() performed is that if it was called with both s[]
and r[] uninitialized, it will first try to initialize them with the
data from the first "block" that it believed to be 32 bytes in length.
First 16 bytes are used as the key and the next 16 bytes for s[]. This
would lead to the aforementioned read out-of-bound. However, after
calling poly1305_init_arch(), only 16 bytes were deducted from the input
and s[] is initialized yet again with the following 16 bytes. The second
initialization of s[] is certainly redundent which indicates that the
first initialization should be for r[] only.

This patch fixes the issue by calling poly1305_init_arm64() instead o
---truncated---

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

## Which versions are affected by CVE-2022-50231?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-50231?

Apply the vendor's patch.

## Is CVE-2022-50231 being exploited?

There is no known exploitation of CVE-2022-50231 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-2022-50231 and fix it if it is affected.

What it is: CVE-2022-50231 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Jun 2025. 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-2022-50231 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-2022-50231/ (Markdown: https://insights.sbomify.com/CVE-2022-50231/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-50231
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-50231
- OSV: https://osv.dev/vulnerability/CVE-2022-50231

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-50231/
Summaries are generated and may contain mistakes; the official description above is the record.