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CVE-2026-46132

net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo

publishedCWE-908

In the Linux kernel, the following vulnerability has been resolved: net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo rtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack without initialisation: struct ifla_vf_broadcast vf_broadcast; The struct contains a single fixed 32-byte field: /* include/uapi/linux/if_link.h */ struct ifla_vf_broadcast { __u8 broadcast[32]; }; The function then copies dev->broadcast into it using dev->addr_len as the length: memcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len); On Ethernet devices (the overwhelming majority of SR-IOV NICs) dev->addr_len is 6, so only the first 6 bytes of broadcast[] are written. The remaining 26 bytes retain whatever was previously on the kernel stack. The full struct is then handed to userspace via: nla_put(skb, IFLA_VF_BROADCAST, sizeof(vf_broadcast), &vf_broadcast) leaking up to 26 bytes of uninitialised kernel stack per VF per RTM_GETLINK request, repeatable. The other vf_* structs in the same function are explicitly zeroed for exactly this reason - see the memset() calls for ivi, vf_vlan_info, node_guid and port_guid a few lines above. vf_broadcast was simply missed when it was added. Reachability: any unprivileged local process can open AF_NETLINK / NETLINK_ROUTE without capabilities and send RTM_GETLINK with an IFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks each VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per VF per request. Stack residue at this call site can include return addresses and transient sensitive data; KASAN with stack instrumentation, or KMSAN, will flag the nla_put() when reproduced. Zero the on-stack struct before the partial memcpy, matching the existing pattern used for the other vf_* structs in the same function.

Technical severity5.5 mediumCVSS 3.1 · NVD: [email protected]

Published2026-05-28Source updated 2026-11-10

Collected2026-11-103 attributed sources

Fixes and workarounds

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Linux Linux	≥ 75345f888f700c4ab2448287e35d48c760b202e6; < 14271b401ec6a4bf0d88054106fc2956084717e1 (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < cccce3190ba4356432b9f22369b56123d3d89f0d (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < a44fbb631cba646532f3948636626f81717365a7 (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < 0653c0516234c8258975d268a749115fc0f0ff00 (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8 (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < fbe0e6197225e6a83cf113a67a4b425f8de0bcd5 (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < 38bcc21f52246badb3154b6158dcb381d98de011 (affected, git) ≥ 75345f888f700c4ab2448287e35d48c760b202e6; < 4b9e327991815e128ad3af75c3a04630a63ce3e0 (affected, git) Other versions: unaffected	CNA: Linux
Linux Linux	5.3 (affected) ≥ 0; < 5.3 (unaffected, semver) ≥ 5.10.258; ≤ 5.10.* (unaffected, semver) ≥ 5.15.209; ≤ 5.15.* (unaffected, semver) ≥ 6.1.175; ≤ 6.1.* (unaffected, semver) ≥ 6.6.140; ≤ 6.6.* (unaffected, semver) ≥ 6.12.88; ≤ 6.12.* (unaffected, semver) ≥ 6.18.30; ≤ 6.18.* (unaffected, semver) ≥ 7.0.7; ≤ 7.0.* (unaffected, semver) ≥ 7.1; ≤ * (unaffected, original_commit_for_fix) Other versions: affected	CNA: Linux
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

NVD applicability configurations (1)

These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.

[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.10.258",
            "versionStartIncluding": "5.3",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.15.209",
            "versionStartIncluding": "5.11",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.1.175",
            "versionStartIncluding": "5.16",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.6.140",
            "versionStartIncluding": "6.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.12.88",
            "versionStartIncluding": "6.7",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.18.30",
            "versionStartIncluding": "6.13",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "7.0.7",
            "versionStartIncluding": "6.19",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 5.5 medium	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`	NVD: [email protected]

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://git.kernel.org/stable/c/14271b401ec6a4bf0d88054106fc2956084717e1CNA: Linux
https://git.kernel.org/stable/c/cccce3190ba4356432b9f22369b56123d3d89f0dCNA: Linux
https://git.kernel.org/stable/c/a44fbb631cba646532f3948636626f81717365a7CNA: Linux
https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00CNA: Linux
https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8CNA: Linux
https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5CNA: Linux
https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011CNA: Linux
https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0CNA: Linux
https://cert-portal.siemens.com/productcert/html/ssa-019113.htmlADP: siemens-SADP
https://cert-portal.siemens.com/productcert/html/ssa-457936.htmlADP: siemens-SADP
https://git.kernel.org/stable/c/0653c0516234c8258975d268a749115fc0f0ff00416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/14271b401ec6a4bf0d88054106fc2956084717e1416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/38bcc21f52246badb3154b6158dcb381d98de011416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/4b9e327991815e128ad3af75c3a04630a63ce3e0416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/a44fbb631cba646532f3948636626f81717365a7416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/c5b1b92ab7eff1a6e8c507ddde6fd02fabd0cfa8416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/cccce3190ba4356432b9f22369b56123d3d89f0d416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/fbe0e6197225e6a83cf113a67a4b425f8de0bcd5416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
https://cert-portal.siemens.com/productcert/html/ssa-457936.html0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

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