CVE-2026-64522 (GCVE-0-2026-64522)

Vulnerability from cvelistv5 – Published: 2026-07-25 09:14 – Updated: 2026-08-05 12:42
VLAI
Title
net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA
Summary
In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA mlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating software state and skipping hardware offload setup. That path jumps to the common success label before taking the eswitch mode block. After tunnel-mode validation was moved earlier, the common success label unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs, this decrements esw->offloads.num_block_mode without a matching increment. Return directly after installing the acquire SA offload handle, so only the paths that successfully called mlx5_eswitch_block_mode() call the matching unblock.
Severity
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 22239eb258bc1e6ccdb2d3502fce1cc2b2a88386 , < b5bd4249e430f5963d559708ee96a671716d2400 (git)
Affected: 22239eb258bc1e6ccdb2d3502fce1cc2b2a88386 , < ecafd8284e527666e83261e6e57a7c7341d591cb (git)
Affected: 22239eb258bc1e6ccdb2d3502fce1cc2b2a88386 , < abe003b33223ff33552f291644bf35d9c2f992fb (git)
Affected: 993c4ba71596c30418ba5a0ddcf4f9c2f431466a (git)
Affected: 6.17.4 , < 6.18 (semver)
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Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "b5bd4249e430f5963d559708ee96a671716d2400",
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          ],
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          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "6.18"
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA\n\nmlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating\nsoftware state and skipping hardware offload setup.\n\nThat path jumps to the common success label before taking the eswitch mode\nblock. After tunnel-mode validation was moved earlier, the common success\nlabel unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs,\nthis decrements esw-\u003eoffloads.num_block_mode without a matching increment.\n\nReturn directly after installing the acquire SA offload handle, so only the\npaths that successfully called mlx5_eswitch_block_mode() call the matching\nunblock."
        }
      ],
      "metrics": [
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - A remote TCP SYN can cause the kernel to route a SYN-ACK through an administrator-configured outbound mlx5 IPsec policy, reaching xfrm_state_find() and the vulnerable acquire-SA callback.\nAC:L - Once the affected packet-offload policy is deployed without a matching SA, the first matching flow deterministically performs the unmatched decrement; no race must be won.\nPR:N - The remote peer needs no credentials or capabilities; configuring the mlx5 IPsec policy is a deployment prerequisite, not an attacker privilege.\nUI:R - The highest-impact stale-object path requires an administrator to request an eswitch mode transition after the attacker has cancelled the live mode-block reference.\nS:U - The resulting corruption affects the same host kernel and mlx5 device security authority, without crossing a VM, IOMMU, or sandbox boundary.\nC:H - The incorrectly permitted mode transition frees mlx5 IPsec structures while XFRM policies retain references to them, creating subsequent use-after-free callbacks capable of exposing kernel memory.\nI:H - The stale policy and flow-table references can be reclaimed and attacker-influenced, making the resulting kernel use-after-free potentially exploitable for arbitrary writes or control-flow hijacking.\nA:H - Mode-transition teardown or later automatic policy expiration can dereference freed IPsec and flow-rule objects, causing a kernel warning, oops, or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:42:35.590Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/b5bd4249e430f5963d559708ee96a671716d2400"
        },
        {
          "url": "https://git.kernel.org/stable/c/ecafd8284e527666e83261e6e57a7c7341d591cb"
        },
        {
          "url": "https://git.kernel.org/stable/c/abe003b33223ff33552f291644bf35d9c2f992fb"
        }
      ],
      "title": "net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64522",
    "datePublished": "2026-07-25T09:14:47.404Z",
    "dateReserved": "2026-07-19T15:36:31.794Z",
    "dateUpdated": "2026-08-05T12:42:35.590Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-22",
      "epss": "0.00342",
      "percentile": "0.2787"
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                "programFiles": [
                  "drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c"
                ],
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA\n\nmlx5e_xfrm_add_state() handles acquire-flow temporary SAs by allocating\nsoftware state and skipping hardware offload setup.\n\nThat path jumps to the common success label before taking the eswitch mode\nblock. After tunnel-mode validation was moved earlier, the common success\nlabel unconditionally calls mlx5_eswitch_unblock_mode(). For acquire SAs,\nthis decrements esw-\u003eoffloads.num_block_mode without a matching increment.\n\nReturn directly after installing the acquire SA offload handle, so only the\npaths that successfully called mlx5_eswitch_block_mode() call the matching\nunblock."
          }
        ],
        "id": "CVE-2026-64522",
        "lastModified": "2026-07-27T05:16:56.213",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
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                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-07-25T10:17:38.497",
        "references": [
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            "url": "https://git.kernel.org/stable/c/abe003b33223ff33552f291644bf35d9c2f992fb"
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        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-07-29T13:28:19+00:00",
      "cve": "CVE-2026-64522",
      "id": "CVE-2026-64522",
      "initial_release_date": "2026-07-25T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/mlx5e: Fix eswitch mode block underflow on IPsec acquire SA",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64522.json",
      "version": "3"
    }
  }
}



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