CVE-2026-89838 (GCVE-0-2026-89838)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:31 – Updated: 2026-09-21 13:15
VLAI
Title
f2fs: limit recovery filename logging to stored length
Summary
In the Linux kernel, the following vulnerability has been resolved: f2fs: limit recovery filename logging to stored length F2FS stores recovery filenames as a length plus a fixed-size i_name buffer. The buffer is not NUL-terminated, but recover_inode() and recover_dentry() print it with %s. For a 255-byte filename, recovery logging can read past i_name into the following raw inode fields. Print the name with a precision bounded by i_namelen and F2FS_NAME_LEN.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f356fe0cba0e3523e538987916bd2acedd4e6f41 , < 35c5abccd0924b02ad34126f562d93c8d75b0831 (git)
Affected: f356fe0cba0e3523e538987916bd2acedd4e6f41 , < 317d32e1a8deaf1c01c388badc667334c39e62ca (git)
Affected: f356fe0cba0e3523e538987916bd2acedd4e6f41 , < 01027b2fcb74dade59fb833b51023f6593b6a9a2 (git)
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Linux Linux Affected: 3.11
Unaffected: 0 , < 3.11 (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/f2fs/recovery.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "35c5abccd0924b02ad34126f562d93c8d75b0831",
              "status": "affected",
              "version": "f356fe0cba0e3523e538987916bd2acedd4e6f41",
              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
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              "version": "3.11"
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "version": "6.18.53",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                },
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                  "vulnerable": true
                },
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                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "3.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: limit recovery filename logging to stored length\n\nF2FS stores recovery filenames as a length plus a fixed-size i_name\nbuffer.  The buffer is not NUL-terminated, but recover_inode() and\nrecover_dentry() print it with %s.\n\nFor a 255-byte filename, recovery logging can read past i_name into the\nfollowing raw inode fields.\n\nPrint the name with a precision bounded by i_namelen and F2FS_NAME_LEN."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - recover_inode() and recover_dentry() run only during local f2fs roll-forward in f2fs_fill_super() -\u003e f2fs_recover_fsync_data(). This is a local block filesystem (Android userdata/portable storage), not a network protocol path such as ksmbd or nfsd.\nAC:L - A crafted f2fs image with a 255-byte non-NUL i_name and a pending fsync node makes printk %s over-read deterministically on mount. Roll-forward is default-enabled; no race or attacker-uncontrollable layout is required.\nPR:L - f2fs lacks FS_USERNS_MOUNT, but Android vold auto-mounts f2fs portable/adoptable storage and desktop/kiosk udisks2/polkit mounts removable media for an ordinary console user, so init-namespace root is not required.\nUI:N - The attacker supplies the crafted image; vold/udisks auto-mount runs roll-forward recovery without a separate deliberate victim mount or open. Recovery also fires automatically on the next mount after an unclean shutdown.\nS:U - The over-read and any resulting oops stay in the host kernel address space and security authority. This is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - recover_inode()/recover_dentry() pass the 255-byte, non-NUL-terminated i_name to printk %s with no precision, so vsprintf scans past the field and the rest of the 4KB node folio into adjacent kernel memory and copies it into dmesg, an unbounded OOB read.\nI:N - The defect is a read-only printk over-read of i_name; it does not write kernel memory, corrupt adjacent objects, or provide a control-flow hijack primitive.\nA:H - Unbounded %s scanning off the node folio can walk into unmapped pages or trip KASAN/page-poisoning and oops/panic the kernel during mount recovery, fully denying availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T13:15:07.386Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/35c5abccd0924b02ad34126f562d93c8d75b0831"
        },
        {
          "url": "https://git.kernel.org/stable/c/317d32e1a8deaf1c01c388badc667334c39e62ca"
        },
        {
          "url": "https://git.kernel.org/stable/c/01027b2fcb74dade59fb833b51023f6593b6a9a2"
        }
      ],
      "title": "f2fs: limit recovery filename logging to stored length",
      "x_generator": {
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      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89838",
    "datePublished": "2026-09-16T10:31:12.746Z",
    "dateReserved": "2026-09-11T19:38:34.769Z",
    "dateUpdated": "2026-09-21T13:15:07.386Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-25",
      "epss": "0.00164",
      "percentile": "0.04959"
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    "nvd": {
      "cve": {
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            "affectedData": [
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                "product": "Linux",
                "programFiles": [
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                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
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                "versions": [
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                    "version": "0",
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                    "version": "6.18.53",
                    "versionType": "semver"
                  },
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                    "status": "unaffected",
                    "version": "7.2.5",
                    "versionType": "semver"
                  },
                  {
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                    "status": "unaffected",
                    "version": "7.3-rc1",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: limit recovery filename logging to stored length\n\nF2FS stores recovery filenames as a length plus a fixed-size i_name\nbuffer.  The buffer is not NUL-terminated, but recover_inode() and\nrecover_dentry() print it with %s.\n\nFor a 255-byte filename, recovery logging can read past i_name into the\nfollowing raw inode fields.\n\nPrint the name with a precision bounded by i_namelen and F2FS_NAME_LEN."
          }
        ],
        "id": "CVE-2026-89838",
        "lastModified": "2026-09-21T14:17:27.383",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
                "version": "3.1"
              },
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              "impactScore": 5.2,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
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        "published": "2026-09-16T11:16:50.620",
        "references": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/01027b2fcb74dade59fb833b51023f6593b6a9a2"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/317d32e1a8deaf1c01c388badc667334c39e62ca"
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          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/35c5abccd0924b02ad34126f562d93c8d75b0831"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.