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.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade perfUpgrade python-perf-debuginfoUpgrade kernel-livepatch-5.10.192-182.736Upgrade kernel-livepatch-5.15.128-80.144Upgrade kernelUpgrade kernel-toolsUpgrade kernel-debuginfo-common-x86_64Upgrade python-perfUpgrade kernel-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-develUpgrade perf-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-tools-debuginfoUpgrade kernel-headersUpgrade bpftoolUpgrade kernel-tools-devel | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade kernel-headersUpgrade kernelUpgrade kernel-toolsUpgrade kernel-libbpf-develUpgrade perf-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-libbpf-staticUpgrade python3-perfUpgrade kernel-tools-develUpgrade perfUpgrade kernel-livepatch-6.1.49-69.116Upgrade kernel-tools-debuginfoUpgrade kernel-libbpfUpgrade kernel-debuginfo-common-x86_64Upgrade bpftoolUpgrade bpftool-debuginfoUpgrade kernel-develUpgrade kernel-debuginfoUpgrade python3-perf-debuginfo | Oct 16, 2025 | Sep 18, 2025 |
| Debian | — | Upgrade linux | Sep 22, 2025 | Sep 22, 2025 |
| Huawei Euleros 2_0_sp13 | — | Upgrade kernel-tools-libsUpgrade kernel-toolsUpgrade python3-perfUpgrade bpftoolUpgrade kernel-abi-stablelistsUpgrade kernel | Mar 10, 2026 | Mar 10, 2026 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Sep 18, 2025 |
| Ubuntu | — | Upgrade linux-hwe-5.4Upgrade linux-iotUpgrade linux-ibmUpgrade linux-hwe-5.15Upgrade linux-raspi-5.4Upgrade linux-kvmUpgrade linux-gkeopUpgrade linux-azure-5.15Upgrade linux-awsUpgrade linux-azure-5.4Upgrade linux-nvidia-tegra-igxUpgrade linux-gcp-5.15Upgrade linux-gcpUpgrade linux-nvidiaUpgrade linux-gcp-fipsUpgrade linux-aws-fipsUpgrade linux-xilinx-zynqmpUpgrade linux-intel-iotg-5.15Upgrade linux-intel-iot-realtimeUpgrade linux-azure-fipsUpgrade linux-oracleUpgrade linux-gcp-5.4Upgrade linux-azureUpgrade linux-nvidia-tegraUpgrade linux-fipsUpgrade linux-oracle-5.4Upgrade linux-bluefieldUpgrade linux-aws-5.15Upgrade linux-aws-5.4Upgrade linux-ibm-5.15Upgrade linux-oracle-5.15Upgrade linuxUpgrade linux-nvidia-tegra-5.15Upgrade linux-raspiUpgrade linux-realtimeUpgrade linux-lowlatency-hwe-5.15Upgrade linux-gkeUpgrade linux-lowlatencyUpgrade linux-riscv-5.15Upgrade linux-ibm-5.4Upgrade linux-intel-iotg | Sep 26, 2025 | Sep 18, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Sep 18, 2025 |
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