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CVE-2026-89606 (GCVE-0-2026-89606)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:45 – Updated: 2026-09-14 12:01
VLAI
Title
ecryptfs: reject too-small tag 70 packets
Summary
In the Linux kernel, the following vulnerability has been resolved: ecryptfs: reject too-small tag 70 packets ecryptfs_parse_tag_70_packet() subtracts fixed metadata fields from the parsed packet body size to derive the encrypted filename size. A malformed packet with a body smaller than those fixed fields can underflow that size calculation. Reject tag 70 packets before the subtraction unless the body contains the signature, cipher code, and at least one byte of encrypted filename data.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < df5f375a6151ef71f636da044bcef90c26697255 (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < 5668121974eb7f7aa82793a9d0d13abadb8904dc (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < 2e5afed9503dd1d85004c09503adc2cb584c0188 (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < 414a0f04feb06f03523edf7e2a8be1d7f1a9b160 (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < 9d88391bbed76eb091cddd50b0af87b1c6f22589 (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < b31da1ecf13929a8d7f8d2727843d2fe35396b75 (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < d2869768eab5648e6edc05f47e0716e5328e6681 (git)
Affected: 9c79f34f7ee71cd28272332b424ca64b2be006ab , < e97bbe1b2bd82ec2ae37ad2e4965b4d3e78bbf7f (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.29
Unaffected: 0 , < 2.6.29 (semver)
Unaffected: 5.10.270 , ≤ 5.10.* (semver)
Unaffected: 5.15.221 , ≤ 5.15.* (semver)
Unaffected: 6.1.188 , ≤ 6.1.* (semver)
Unaffected: 6.6.157 , ≤ 6.6.* (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\necryptfs: reject too-small tag 70 packets\n\necryptfs_parse_tag_70_packet() subtracts fixed metadata fields from the\nparsed packet body size to derive the encrypted filename size.  A\nmalformed packet with a body smaller than those fixed fields can underflow\nthat size calculation.\n\nReject tag 70 packets before the subtraction unless the body contains the\nsignature, cipher code, and at least one byte of encrypted filename data."
        }
      ],
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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          "scenarios": [
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              "lang": "en",
              "value": "AV:L - The bug is reached only through local VFS operations on an eCryptfs mount with filename encryption: getdents via ecryptfs_filldir() and readlink via ecryptfs_get_link(), which decode lower-filesystem names or symlink targets into tag 70 packets. No network protocol or remote peer data is parsed.\nAC:L - An attacker who can create names on the lower filesystem fully controls the tag-70 length byte and can copy a valid FNEK signature from their own mount or existing encrypted names, so the unsigned size wrap is deterministic with no race or uninfluenced condition.\nPR:L - Unprivileged users reach this on standard eCryptfs deployments (encrypted home/Private via setuid mount.ecryptfs_private, or an already-mounted per-user eCryptfs directory) by writing the lower directory they own; triggering does not require init-namespace root.\nUI:N - The attacker plants the malformed ECRYPTFS_FNEK_ENCRYPTED name or lower symlink target and then issues getdents or readlink on their own eCryptfs mount; no separate victim action is required, and in the encrypted-home case the mount already exists at login.\nS:U - Memory corruption and oops stay inside the host kernel\u0027s eCryptfs/VFS context. This is ordinary kernel impact, not a VM, IOMMU, or sandbox-boundary escape.\nC:H - The underflowed block_aligned_filename_size is used as the scatterlist, kmalloc, and skcipher-decrypt length for the encrypted filename, so a wrapped length becomes an out-of-bounds read of kernel memory adjacent to the decoded packet buffer.\nI:H - The same wrapped length is the destination size for kmalloc plus crypto_skcipher_decrypt and the subsequent memcpy of the decrypted name, yielding an out-of-bounds write into heap/crypto scratch buffers that can be used for control-flow hijack.\nA:H - virt_to_scatterlist() returns 0 for the wrapped size without the caller setting rc, so parse_tag_70_packet() returns success with a NULL filename; ecryptfs_get_link() then does buf[len]=\u0027\\0\u0027 on that NULL pointer and oopses the kernel."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "title": "ecryptfs: reject too-small tag 70 packets",
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    "dateReserved": "2026-09-11T19:38:34.733Z",
    "dateUpdated": "2026-09-14T12:01:26.751Z",
    "state": "PUBLISHED"
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A\\nmalformed packet with a body smaller than those fixed fields can underflow\\nthat size calculation.\\n\\nReject tag 70 packets before the subtraction unless the body contains the\\nsignature, cipher code, and at least one byte of encrypted filename data.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/ecryptfs/keystore.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"df5f375a6151ef71f636da044bcef90c26697255\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"5668121974eb7f7aa82793a9d0d13abadb8904dc\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"2e5afed9503dd1d85004c09503adc2cb584c0188\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"414a0f04feb06f03523edf7e2a8be1d7f1a9b160\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"9d88391bbed76eb091cddd50b0af87b1c6f22589\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"b31da1ecf13929a8d7f8d2727843d2fe35396b75\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"d2869768eab5648e6edc05f47e0716e5328e6681\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"9c79f34f7ee71cd28272332b424ca64b2be006ab\",\"lessThan\":\"e97bbe1b2bd82ec2ae37ad2e4965b4d3e78bbf7f\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/ecryptfs/keystore.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.29\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.29\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.270\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.221\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.188\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.157\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.109\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.50\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.4\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2e5afed9503dd1d85004c09503adc2cb584c0188\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/414a0f04feb06f03523edf7e2a8be1d7f1a9b160\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5668121974eb7f7aa82793a9d0d13abadb8904dc\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9d88391bbed76eb091cddd50b0af87b1c6f22589\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b31da1ecf13929a8d7f8d2727843d2fe35396b75\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d2869768eab5648e6edc05f47e0716e5328e6681\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/df5f375a6151ef71f636da044bcef90c26697255\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e97bbe1b2bd82ec2ae37ad2e4965b4d3e78bbf7f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-13T06:58:57+00:00",
      "cve": "CVE-2026-89606",
      "id": "CVE-2026-89606",
      "initial_release_date": "2026-09-11T19:45:08.832000+00:00",
      "product_status:known_affected": "2",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ecryptfs: Denial of Service via malformed tag 70 packets",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89606.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-16T00:01:42Z",
      "cve": "CVE-2026-89606",
      "id": "CVE-2026-89606",
      "initial_release_date": "2026-09-12T16:25:14Z",
      "product_status:known_affected": "353",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-89606",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-89606.json",
      "version": "4"
    }
  }
}



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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.

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  • 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.
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  • 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.


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