# CVE-2026-46172: ipv6: xfrm6: release dst on error in xfrm6_rcv_encap()

Status: published. Published: 2026-05-28. Updated: 2026-11-10.

In the Linux kernel, the following vulnerability has been resolved:

ipv6: xfrm6: release dst on error in xfrm6_rcv_encap()

xfrm6_rcv_encap() performs an IPv6 route lookup when the skb does not
already have a dst attached. ip6_route_input_lookup() returns a
referenced dst entry even when the lookup resolves to an error route.

If dst->error is set, xfrm6_rcv_encap() drops the skb without attaching
the dst to the skb and without releasing the reference returned by the
lookup. Repeated packets hitting this path therefore leak dst entries.

Release the dst before jumping to the drop path.

## Remediation

- 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) — https://git.kernel.org/stable/c/554c9b090c8ac5b1c5c507f4badf8d5d0c9c6e13
- 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) — https://git.kernel.org/stable/c/6a5eec0a2a0e99ec9743cf8f1c4082178811d90a
- 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) — https://git.kernel.org/stable/c/870560015ce6e0d8f841c6a8aba33c44be52c727
- 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) — https://git.kernel.org/stable/c/9d5047782f9bd2829e529df69209bf3232eb561f
- 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) — https://git.kernel.org/stable/c/a0721bcd72641c32b281f227a94505b31cf54117
- 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) — https://git.kernel.org/stable/c/a20b34f6e854fe6f2aa82528fae7a88759919eb4
- 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) — https://git.kernel.org/stable/c/bc0fcb9823cd0894934cf968b525c575833d7078
- 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) — https://git.kernel.org/stable/c/c2efc4956981066df2fef1cc77391b523db6d8e4

## Affected products and versions

- Linux / Linux: ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < a0721bcd72641c32b281f227a94505b31cf54117 (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < a20b34f6e854fe6f2aa82528fae7a88759919eb4 (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < 870560015ce6e0d8f841c6a8aba33c44be52c727 (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < c2efc4956981066df2fef1cc77391b523db6d8e4 (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < 554c9b090c8ac5b1c5c507f4badf8d5d0c9c6e13 (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < 9d5047782f9bd2829e529df69209bf3232eb561f (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < 6a5eec0a2a0e99ec9743cf8f1c4082178811d90a (affected, git); ≥ 0146dca70b877b73c5fd9c67912b8a0ca8a7bac7; < bc0fcb9823cd0894934cf968b525c575833d7078 (affected, git). Source: CNA: Linux
- Linux / Linux: 5.8 (affected); ≥ 0; < 5.8 (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). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 TM MFP - GNU/Linux subsystem: ≥ 0; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.10.258",
            "versionStartIncluding": "5.8",
            "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"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: NVD: nvd@nist.gov

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-09; percentile 2.96%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

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

## References

- https://git.kernel.org/stable/c/a0721bcd72641c32b281f227a94505b31cf54117 (CNA: Linux)

- https://git.kernel.org/stable/c/a20b34f6e854fe6f2aa82528fae7a88759919eb4 (CNA: Linux)

- https://git.kernel.org/stable/c/870560015ce6e0d8f841c6a8aba33c44be52c727 (CNA: Linux)

- https://git.kernel.org/stable/c/c2efc4956981066df2fef1cc77391b523db6d8e4 (CNA: Linux)

- https://git.kernel.org/stable/c/554c9b090c8ac5b1c5c507f4badf8d5d0c9c6e13 (CNA: Linux)

- https://git.kernel.org/stable/c/9d5047782f9bd2829e529df69209bf3232eb561f (CNA: Linux)

- https://git.kernel.org/stable/c/6a5eec0a2a0e99ec9743cf8f1c4082178811d90a (CNA: Linux)

- https://git.kernel.org/stable/c/bc0fcb9823cd0894934cf968b525c575833d7078 (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (ADP: siemens-SADP)

- https://git.kernel.org/stable/c/554c9b090c8ac5b1c5c507f4badf8d5d0c9c6e13 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/6a5eec0a2a0e99ec9743cf8f1c4082178811d90a (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/870560015ce6e0d8f841c6a8aba33c44be52c727 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/9d5047782f9bd2829e529df69209bf3232eb561f (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/a0721bcd72641c32b281f227a94505b31cf54117 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/a20b34f6e854fe6f2aa82528fae7a88759919eb4 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/bc0fcb9823cd0894934cf968b525c575833d7078 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/c2efc4956981066df2fef1cc77391b523db6d8e4 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (0b142b55-0307-4c5a-b3c9-f314f3fb7c5e)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (0b142b55-0307-4c5a-b3c9-f314f3fb7c5e)

- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (0b142b55-0307-4c5a-b3c9-f314f3fb7c5e)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-46172; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46172; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-46172; retrieved 2026-11-10; source updated Not reported

Revision: 254fab35cf2fa947117e8dd9b28ac67b2ee9a8cdb92b176c95d362c081f2a33f

Canonical: https://y2.dev/cve/CVE-2026-46172

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