# CVE-2026-53249: ipv4: restrict IPOPT_SSRR and IPOPT_LSRR options

Status: published. Published: 2026-06-25. Updated: 2026-11-10.

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

ipv4: restrict IPOPT_SSRR and IPOPT_LSRR options

This patch restricts setting Loose Source and Record Route (LSRR)
and Strict Source and Record Route (SSRR) IP options to users
with CAP_NET_RAW capability.

This prevents unprivileged applications from forcing packets to route
through attacker-controlled nodes to leak TCP ISN and possibly other
protocol information.

While LSRR and SSRR are commonly filtered in many network environments,
they may still be supported and forwarded along some network paths.

RFC 7126 (Recommendations on Filtering of IPv4 Packets Containing
IPv4 Options) recommend to drop these options in 4.3 and 4.4.

## 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/00e8845fe3428c69e980dce5071cb3da1d8f7578
- 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/28f5ad1b4055405eb1616e603fe511ba5e3725e7
- 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/2a87c3e8f03ce655ed0ef500d64d5fd924ec3691
- 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/4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2
- 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/89343ff12b3178fc236fe531a3603e7c97c68278
- 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/8ff85dbabbbfb05e86e6cde31d91ac5782179d4d
- 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/a4f3fd6516920988c47ba8d19714985c40c816a1
- 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/d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c

## Affected products and versions

- Linux / Linux: ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 2a87c3e8f03ce655ed0ef500d64d5fd924ec3691 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 89343ff12b3178fc236fe531a3603e7c97c68278 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 8ff85dbabbbfb05e86e6cde31d91ac5782179d4d (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 00e8845fe3428c69e980dce5071cb3da1d8f7578 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < a4f3fd6516920988c47ba8d19714985c40c816a1 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < 28f5ad1b4055405eb1616e603fe511ba5e3725e7 (affected, git); ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2; < d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.12 (affected); ≥ 0; < 2.6.12 (unaffected, semver); ≥ 5.10.259; ≤ 5.10.* (unaffected, semver); ≥ 5.15.210; ≤ 5.15.* (unaffected, semver); ≥ 6.1.176; ≤ 6.1.* (unaffected, semver); ≥ 6.6.143; ≤ 6.6.* (unaffected, semver); ≥ 6.12.94; ≤ 6.12.* (unaffected, semver); ≥ 6.18.36; ≤ 6.18.* (unaffected, semver); ≥ 7.0.13; ≤ 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": "5.10.259",
            "versionStartIncluding": "2.6.12.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.15.210",
            "versionStartIncluding": "5.11",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.1.176",
            "versionStartIncluding": "5.16",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.6.143",
            "versionStartIncluding": "6.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.12.94",
            "versionStartIncluding": "6.7",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.18.36",
            "versionStartIncluding": "6.13",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "7.0.13",
            "versionStartIncluding": "6.19",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*",
            "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
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:*",
            "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 2.54%

- 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/4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2 (CNA: Linux)

- https://git.kernel.org/stable/c/2a87c3e8f03ce655ed0ef500d64d5fd924ec3691 (CNA: Linux)

- https://git.kernel.org/stable/c/89343ff12b3178fc236fe531a3603e7c97c68278 (CNA: Linux)

- https://git.kernel.org/stable/c/8ff85dbabbbfb05e86e6cde31d91ac5782179d4d (CNA: Linux)

- https://git.kernel.org/stable/c/00e8845fe3428c69e980dce5071cb3da1d8f7578 (CNA: Linux)

- https://git.kernel.org/stable/c/a4f3fd6516920988c47ba8d19714985c40c816a1 (CNA: Linux)

- https://git.kernel.org/stable/c/28f5ad1b4055405eb1616e603fe511ba5e3725e7 (CNA: Linux)

- https://git.kernel.org/stable/c/d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c (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/00e8845fe3428c69e980dce5071cb3da1d8f7578 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/28f5ad1b4055405eb1616e603fe511ba5e3725e7 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/2a87c3e8f03ce655ed0ef500d64d5fd924ec3691 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/89343ff12b3178fc236fe531a3603e7c97c68278 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/8ff85dbabbbfb05e86e6cde31d91ac5782179d4d (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/a4f3fd6516920988c47ba8d19714985c40c816a1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c (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-2026-53249; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53249; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-53249; retrieved 2026-11-10; source updated Not reported

Revision: a00abb36ff3533ff567ce97aa3c9068867fbb7c2b1b824f5043f084e3d5c8be4

Canonical: https://y2.dev/cve/CVE-2026-53249

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