CVE-2026-99177 (GCVE-0-2026-99177)

Vulnerability from cvelistv5 – Published: 2026-10-28 10:35 – Updated: 2026-10-31 12:44
VLAI
Title
KVM: SEV: Fix page dirtying in sev_gmem_post_populate()
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Fix page dirtying in sev_gmem_post_populate() set_page_dirty() requires that the caller holds some kind of lock to ensure that the page's mapping does not concurrently go away. That is not the case for a random page we got from get_user_pages_fast(), so use set_page_dirty_lock(). [sean: tag for stable]
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6653 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 97cd21d57e9bd2da79845178d9250cfd19289cd4 , < 184382f9852d433af21de96c334ecf43b8414ed8 (git)
Affected: 97cd21d57e9bd2da79845178d9250cfd19289cd4 , < 97818b2fa7082e940ddd36dab12a68615300e798 (git)
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Linux Linux Affected: 7.2
Unaffected: 0 , < 7.2 (semver)
Unaffected: 7.2.13 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "versionType": "git"
            },
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
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          "product": "Linux",
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          ],
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          "vendor": "Linux",
          "versions": [
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              "version": "7.2"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.13",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Fix page dirtying in sev_gmem_post_populate()\n\nset_page_dirty() requires that the caller holds some kind of lock to\nensure that the page\u0027s mapping does not concurrently go away.\nThat is not the case for a random page we got from get_user_pages_fast(),\nso use set_page_dirty_lock().\n\n[sean: tag for stable]"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Local ioctl(KVM_MEMORY_ENCRYPT_OP) follows kvm_vm_ioctl() \u2192 sev_mem_enc_ioctl() \u2192 snp_launch_update() \u2192 kvm_gmem_populate() \u2192 patched sev_gmem_post_populate(); the triggering CPUID page comes from the ioctl\u0027s userspace uaddr, not a network peer or guest.\nAC:L - The caller can supply a CPUID page that makes SEV_CMD_SNP_LAUNCH_UPDATE return SEV_RET_INVALID_PARAM and concurrently tear down its file-backed source mapping; the same attacker controls both sides of the set_page_dirty() race.\nPR:L - kvm_vm_ioctl() requires a same-mm VM fd and __sev_issue_cmd() requires a valid /dev/sev fd, but sev_mem_enc_ioctl() and snp_launch_update() perform no capability check; an unprivileged VMM account granted those device fds suffices.\nUI:N - The attacker creates and initializes the SNP VM, submits the rejected CPUID page, and races teardown of that page\u0027s mapping without any action by another user.\nS:U - The UAF occurs in the host kernel while servicing the host VMM\u0027s launch ioctl; it is not a guest-to-host escape because the guest has not begun executing on this pre-launch failure path.\nC:H - folio_mark_dirty() can invoke mapping-\u003ea_ops-\u003edirty_folio through a freed inode-embedded address_space; grooming the stale object and exploiting the resulting kernel control-flow or mapping-state corruption can provide arbitrary host-kernel memory access.\nI:H - For buffer-backed pages, the stale callback can enter block_dirty_folio(), modify freed mapping locks and buffer state, then call __folio_mark_dirty() and __mark_inode_dirty() through reused objects, providing exploitable UAF writes and potential kernel code execution.\nA:H - The stale dirty_folio callback can dereference freed or poisoned a_ops, spinlocks, buffer heads, or host-inode state, causing a host kernel oops or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-31T12:44:45.294Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/184382f9852d433af21de96c334ecf43b8414ed8"
        },
        {
          "url": "https://git.kernel.org/stable/c/97818b2fa7082e940ddd36dab12a68615300e798"
        }
      ],
      "title": "KVM: SEV: Fix page dirtying in sev_gmem_post_populate()",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-99177",
    "datePublished": "2026-10-28T10:35:31.315Z",
    "dateReserved": "2026-09-25T10:25:14.399Z",
    "dateUpdated": "2026-10-31T12:44:45.294Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-99177",
      "date": "2026-11-08",
      "epss": "0.00121",
      "percentile": "0.01922"
    },
    "nvd": {
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        "affected": [
          {
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              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "arch/x86/kvm/svm/sev.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
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                    "version": "97cd21d57e9bd2da79845178d9250cfd19289cd4",
                    "versionType": "git"
                  },
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                ],
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                "vendor": "Linux",
                "versions": [
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                  },
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                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
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                  }
                ]
              }
            ],
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          }
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Fix page dirtying in sev_gmem_post_populate()\n\nset_page_dirty() requires that the caller holds some kind of lock to\nensure that the page\u0027s mapping does not concurrently go away.\nThat is not the case for a random page we got from get_user_pages_fast(),\nso use set_page_dirty_lock().\n\n[sean: tag for stable]"
          }
        ],
        "id": "CVE-2026-99177",
        "lastModified": "2026-10-31T13:17:58.880",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "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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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-10-28T11:17:38.397",
        "references": [
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            "url": "https://git.kernel.org/stable/c/184382f9852d433af21de96c334ecf43b8414ed8"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/97818b2fa7082e940ddd36dab12a68615300e798"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-11-06T03:28:01+00:00",
      "cve": "CVE-2026-99177",
      "id": "CVE-2026-99177",
      "initial_release_date": "2026-10-28T10:35:31.315000+00:00",
      "product_status:known_affected": "1",
      "product_status:known_not_affected": "203",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: kernel: Denial of Service via improper page dirtying locking in KVM SEV",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-99177.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-11-04T16:00:03Z",
      "cve": "CVE-2026-99177",
      "id": "CVE-2026-99177",
      "initial_release_date": "2026-10-28T17:32:28Z",
      "product_status:known_not_affected": "348",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-99177",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-99177.json",
      "version": "5"
    }
  }
}



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