# CVE-2023-53369: net: dcb: choose correct policy to parse DCB_ATTR_BCN

> Incorrect netlink attribute parsing policy in the Linux kernel DCB module may lead to unexpected behavior or memory issues.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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 Sep 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-53369, DEBIAN-CVE-2023-53369, GHSA-868g-hgv5-rh5v, UBUNTU-CVE-2023-53369

## What is CVE-2023-53369?

CVE-2023-53369 is a medium-severity vulnerability in Linux kernel, published on 18 Sep 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:

net: dcb: choose correct policy to parse DCB_ATTR_BCN

The dcbnl_bcn_setcfg uses erroneous policy to parse tb[DCB_ATTR_BCN],
which is introduced in commit 859ee3c43812 ("DCB: Add support for DCB
BCN"). Please see the comment in below code

static int dcbnl_bcn_setcfg(...)
{
  ...
  ret = nla_parse_nested_deprecated(..., dcbnl_pfc_up_nest, .. )
  // !!! dcbnl_pfc_up_nest for attributes
  //  DCB_PFC_UP_ATTR_0 to DCB_PFC_UP_ATTR_ALL in enum dcbnl_pfc_up_attrs
  ...
  for (i = DCB_BCN_ATTR_RP_0; i <= DCB_BCN_ATTR_RP_7; i++) {
  // !!! DCB_BCN_ATTR_RP_0 to DCB_BCN_ATTR_RP_7 in enum dcbnl_bcn_attrs
    ...
    value_byte = nla_get_u8(data[i]);
    ...
  }
  ...
  for (i = DCB_BCN_ATTR_BCNA_0; i <= DCB_BCN_ATTR_RI; i++) {
  // !!! DCB_BCN_ATTR_BCNA_0 to DCB_BCN_ATTR_RI in enum dcbnl_bcn_attrs
  ...
    value_int = nla_get_u32(data[i]);
  ...
  }
  ...
}

That is, the nla_parse_nested_deprecated uses dcbnl_pfc_up_nest
attributes to parse nlattr defined in dcbnl_pfc_up_attrs. But the
following access code fetch each nlattr as dcbnl_bcn_attrs attributes.
By looking up the associated nla_policy for dcbnl_bcn_attrs. We can find
the beginning part of these two policies are "same".

static const struct nla_policy dcbnl_pfc_up_nest[...] = {
        [DCB_PFC_UP_ATTR_0]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_1]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_2]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_3]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_4]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_5]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_6]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_7]   = {.type = NLA_U8},
        [DCB_PFC_UP_ATTR_ALL] = {.type = NLA_FLAG},
};

static const struct nla_policy dcbnl_bcn_nest[...] = {
        [DCB_BCN_ATTR_RP_0]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_1]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_2]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_3]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_4]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_5]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_6]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_7]         = {.type = NLA_U8},
        [DCB_BCN_ATTR_RP_ALL]       = {.type = NLA_FLAG},
        // from here is somewhat different
        [DCB_BCN_ATTR_BCNA_0]       = {.type = NLA_U32},
        ...
        [DCB_BCN_ATTR_ALL]          = {.type = NLA_FLAG},
};

Therefore, the current code is buggy and this
nla_parse_nested_deprecated could overflow the dcbnl_pfc_up_nest and use
the adjacent nla_policy to parse attributes from DCB_BCN_ATTR_BCNA_0.

Hence use the correct policy dcbnl_bcn_nest to parse the nested
tb[DCB_ATTR_BCN] TLV.

## Which versions are affected by CVE-2023-53369?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53369?

Apply the vendor's patch.

## Is CVE-2023-53369 being exploited?

There is no known exploitation of CVE-2023-53369 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-2023-53369 and fix it if it is affected.

What it is: CVE-2023-53369 is a medium-severity vulnerability in Linux kernel, published on 18 Sep 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-2023-53369 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-2023-53369/ (Markdown: https://insights.sbomify.com/CVE-2023-53369/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53369
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53369
- OSV: https://osv.dev/vulnerability/CVE-2023-53369

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53369/
Summaries are generated and may contain mistakes; the official description above is the record.