Summary
In the Linux kernel, the following vulnerability has been resolved: net: dcb: choose correct...
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.
Impact
CVE-2023-53369 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2023-53369? CVE-2023-53369 is a medium-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2023-53369? CVE-2023-53369 has a CVSS score of 5.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2023-53369? No fixed version is listed for CVE-2023-53369 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2023-53369 exploitable, and should I be worried? Whether CVE-2023-53369 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2023-53369 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.