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CVE-2026-74403 (GCVE-0-2026-74403)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:59 – Updated: 2026-08-17 05:46
VLAI
Title
crypto: ccp - Check for page allocation failure correctly in TIO
Summary
In the Linux kernel, the following vulnerability has been resolved: crypto: ccp - Check for page allocation failure correctly in TIO Sashiko notes: > if __snp_alloc_firmware_pages() returns NULL under memory pressure, is it > safe to pass it directly to page_address()? > > On architectures without HASHED_PAGE_VIRTUAL, page_address(NULL) might > compute a deterministic but invalid, non-zero virtual address. The > subsequent if (tio_status) check would then evaluate to true, and > sev_tsm_init_locked() would dereference the invalid pointer. Indeed, page_address(NULL) will return non-NULL garbage here. Fix this by checking the page allocation itself for NULL, not the resulting virtual address.
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: 4be423572da1f4c11f45168e3fafda870ddac9f8 , < 17e1aae19a06d9f6da4b46d54fa2aeab77ec0c69 (git)
Affected: 4be423572da1f4c11f45168e3fafda870ddac9f8 , < a8d5370eef00eca132a292b1901c9914c817e385 (git)
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Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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              "value": "AV:L - The flaw is in __sev_snp_init_locked() reached only through sev_platform_init() via KVM_SEV_INIT/KVM_SEV_INIT2 ioctls on /dev/kvm or kernel boot init; SEV-TIO platform setup has no network-facing entry point.\nAC:L - An attacker who can trigger first-time SNP init (e.g. psp_init_on_probe=0) can concurrently exhaust host memory to force __snp_alloc_firmware_pages() to return NULL and reliably reach the faulty page_address(NULL) path.\nPR:L - Reaching this code requires opening /dev/kvm and issuing KVM SNP initialization ioctls, which needs CAP_SYS_ADMIN obtainable by an unprivileged user inside a user namespace.\nUI:N - Exploitation needs only attacker-initiated KVM ioctls or boot-time SNP initialization; no action by another user or victim is required.\nS:U - Impact is confined to the host kernel during SNP-TIO initialization (oops, memory corruption); it does not cross a VM, container, or IOMMU security boundary.\nC:H - page_address(NULL) yields a non-NULL direct-map pointer, so sev_tio_init_locked() dereferences invalid memory and passes a bogus physical address to PSP firmware via SEV_CMD_TIO_STATUS, enabling kernel memory disclosure.\nI:H - The invalid pointer causes unchecked reads/writes in sev_tio_init_locked() and may direct PSP firmware to write TIO status data to an unintended physical page, enabling exploitable memory corruption.\nA:H - Dereferencing the bogus page_address(NULL) result in sev_tsm_init_locked()/sev_tio_init_locked() can trigger a kernel oops or panic, crashing the host during SNP-TIO initialization."
            }
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          "url": "https://git.kernel.org/stable/c/a8d5370eef00eca132a292b1901c9914c817e385"
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      "title": "crypto: ccp - Check for page allocation failure correctly in TIO",
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    "cveId": "CVE-2026-74403",
    "datePublished": "2026-08-15T05:59:13.399Z",
    "dateReserved": "2026-08-15T05:44:03.892Z",
    "dateUpdated": "2026-08-17T05:46:45.328Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T13:21:41+00:00",
      "cve": "CVE-2026-74403",
      "id": "CVE-2026-74403",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: crypto: ccp - Check for page allocation failure correctly in TIO",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74403.json",
      "version": "3"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.