FKIE_CVE-2026-53393

Vulnerability from fkie_nvd - Published: 2026-07-19 12:16 - Updated: 2026-07-19 12:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: reset write verifier on deferred writeback errors nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the server's write verifier (nn->writeverf) when this check fails. Every other durable-storage-failure path in these functions calls commit_reset_write_verifier() before returning an error. The missing rotation means clients holding UNSTABLE write data under the current verifier will COMMIT, receive the unchanged verifier back, and conclude their data is durable — silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 §3.3.7, RFC 8881 §18.32). Add commit_reset_write_verifier() calls at both filemap_check_wb_err() error sites, matching the pattern used by adjacent error paths in the same functions. The helper already filters -EAGAIN and -ESTALE internally, so the calls are unconditionally safe.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2090b05803faab8a9fa62fbff871007862cac1b7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/4367afc119c51e17a616f6908772b7e2c2c4013f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b027cca33c97354149fcc0ddeede4525c41093cd
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e",
              "status": "affected",
              "version": "555dbf1a9aac6d3150c8b52fa35f768a692f4eeb",
              "versionType": "git"
            },
            {
              "lessThan": "4367afc119c51e17a616f6908772b7e2c2c4013f",
              "status": "affected",
              "version": "555dbf1a9aac6d3150c8b52fa35f768a692f4eeb",
              "versionType": "git"
            },
            {
              "lessThan": "b027cca33c97354149fcc0ddeede4525c41093cd",
              "status": "affected",
              "version": "555dbf1a9aac6d3150c8b52fa35f768a692f4eeb",
              "versionType": "git"
            },
            {
              "lessThan": "2090b05803faab8a9fa62fbff871007862cac1b7",
              "status": "affected",
              "version": "555dbf1a9aac6d3150c8b52fa35f768a692f4eeb",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f14816f2f928c560d28ba344af689f56efcd6f55",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "3145fe0ebb16e1715ad541a301bc6675c8375fcd",
              "versionType": "git"
            },
            {
              "lessThan": "5.11",
              "status": "affected",
              "version": "5.10.124",
              "versionType": "semver"
            },
            {
              "lessThan": "5.16",
              "status": "affected",
              "version": "5.15.49",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/nfsd/vfs.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.17"
            },
            {
              "lessThan": "5.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.38",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.3",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: reset write verifier on deferred writeback errors\n\nnfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to\ndetect deferred writeback errors, but neither rotates the server\u0027s write\nverifier (nn-\u003ewriteverf) when this check fails. Every other\ndurable-storage-failure path in these functions calls\ncommit_reset_write_verifier() before returning an error.\n\nThe missing rotation means clients holding UNSTABLE write data under the\ncurrent verifier will COMMIT, receive the unchanged verifier back, and\nconclude their data is durable \u2014 silently dropping data that failed\nwriteback. This violates the UNSTABLE+COMMIT durability contract\n(RFC 1813 \u00a73.3.7, RFC 8881 \u00a718.32).\n\nAdd commit_reset_write_verifier() calls at both filemap_check_wb_err()\nerror sites, matching the pattern used by adjacent error paths in the\nsame functions. The helper already filters -EAGAIN and -ESTALE\ninternally, so the calls are unconditionally safe."
    }
  ],
  "id": "CVE-2026-53393",
  "lastModified": "2026-07-19T12:16:50.367",
  "metrics": {},
  "published": "2026-07-19T12:16:50.367",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2090b05803faab8a9fa62fbff871007862cac1b7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/4367afc119c51e17a616f6908772b7e2c2c4013f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b027cca33c97354149fcc0ddeede4525c41093cd"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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