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CVE-2026-68400 (GCVE-0-2026-68400)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:04 – Updated: 2026-08-17 05:04
VLAI
Title
firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation
Summary
In the Linux kernel, the following vulnerability has been resolved: firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation Use the descriptor's `ep_mem_offset` to calculate the start of the endpoint memory access array and to comply with the FF-A spec instead of defaulting to `sizeof(struct ffa_mem_region)`. This requires moving `ffa_mem_region_additional_setup()` earlier in the setup flow. Also, add sanity checks to ensure the calculated descriptor offsets do not exceed `max_fragsize`.
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: 113580530ee7dc61e668b641d657920734533b9f , < b39b08e6bee812514b449dc874076890e6b871a0 (git)
Affected: 113580530ee7dc61e668b641d657920734533b9f , < 8ef18f0ab3c0ec1eac77289f5a542bd96a8a6d66 (git)
Affected: 113580530ee7dc61e668b641d657920734533b9f , < b4d961351aa84fdf0148783fb1f3a1391b8a0adb (git)
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Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfirmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation\n\nUse the descriptor\u0027s `ep_mem_offset` to calculate the start of the endpoint\nmemory access array and to comply with the FF-A spec instead of defaulting\nto `sizeof(struct ffa_mem_region)`.\nThis requires moving `ffa_mem_region_additional_setup()` earlier in the setup\nflow.\nAlso, add sanity checks to ensure the calculated descriptor offsets do not\nexceed `max_fragsize`."
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            "baseSeverity": "HIGH",
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            "version": "3.1"
          },
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              "lang": "en",
              "value": "AV:L - The vulnerable FF-A memory-descriptor setup is reached only through local kernel interfaces \u2014 TEE device ioctls (/dev/tee*) driving optee/tstee shared-memory registration and lend paths, or host-side FF-A SMC handling. No network or remote packet input reaches this code.\nAC:L - The out-of-bounds descriptor writes follow deterministically from the endpoint count and offsets used to build the transaction; no race, no memory-layout luck, and no condition outside the attacker\u0027s influence is needed to drive the unvalidated offset arithmetic past max_fragsize.\nPR:L - An unprivileged local process holding a handle to the TEE device node (common on Android/embedded ARM systems, where TEE clients are ordinary user processes) can drive ffa_setup_and_transmit() via shared-memory registration/lend operations; no root or capability check gates that path.\nUI:N - The vulnerable path is entered directly from the attacker\u0027s own ioctl/FF-A operations; no action by another user or administrator is required.\nS:U - The out-of-bounds writes corrupt kernel memory adjacent to the FF-A TX buffer within the same kernel security authority, so impact is scored as Unchanged even though the same offset confusion also feeds the pKVM/secure-world descriptor parsing.\nC:H - Descriptor offsets computed without validation against max_fragsize let structured data be placed and read back outside the intended buffer, and the resulting heap corruption is leverageable into disclosure of adjacent kernel memory, including data later handed to the secure world.\nI:H - This is an out-of-bounds write of attacker-influenced endpoint descriptor fields (receiver, attrs, composite_off, impdef values) plus a memset past the end of the TX buffer, giving heap corruption that can be groomed into a control-flow or data-structure overwrite primitive.\nA:H - Writing endpoint memory access descriptors beyond the RX/TX buffer corrupts unrelated kernel allocations and readily produces an oops or panic, and the mis-parsed descriptor can also drive the memory transaction into an inconsistent state with the secure partition."
            }
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        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/b4d961351aa84fdf0148783fb1f3a1391b8a0adb"
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    "cveId": "CVE-2026-68400",
    "datePublished": "2026-08-10T12:04:19.952Z",
    "dateReserved": "2026-07-30T09:28:09.389Z",
    "dateUpdated": "2026-08-17T05:04:48.935Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-31T11:27:19+00:00",
      "cve": "CVE-2026-68400",
      "id": "CVE-2026-68400",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_affected": "77",
      "product_status:known_not_affected": "200",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: firmware: arm_ffa: Fix Endpoint Memory Access Descriptor offset calculation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68400.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-13T16:22:20Z",
      "cve": "CVE-2026-68400",
      "id": "CVE-2026-68400",
      "initial_release_date": "2026-08-13T16:22:20Z",
      "product_status:known_affected": "29",
      "product_status:known_not_affected": "267",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68400",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68400.json",
      "version": "2"
    }
  }
}



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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.


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