{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99177","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-09-25T10:25:14.399Z","datePublished":"2026-10-28T10:35:31.315Z","dateUpdated":"2026-10-31T12:44:45.294Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-10-31T12:44:45.294Z"},"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's 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":{"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"},"scenarios":[{"lang":"en","value":"AV:L - Local ioctl(KVM_MEMORY_ENCRYPT_OP) follows kvm_vm_ioctl() → sev_mem_enc_ioctl() → snp_launch_update() → kvm_gmem_populate() → patched sev_gmem_post_populate(); the triggering CPUID page comes from the ioctl's 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's mapping without any action by another user.\nS:U - The UAF occurs in the host kernel while servicing the host VMM's 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->a_ops->dirty_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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/svm/sev.c"],"versions":[{"version":"97cd21d57e9bd2da79845178d9250cfd19289cd4","lessThan":"184382f9852d433af21de96c334ecf43b8414ed8","status":"affected","versionType":"git"},{"version":"97cd21d57e9bd2da79845178d9250cfd19289cd4","lessThan":"97818b2fa7082e940ddd36dab12a68615300e798","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kvm/svm/sev.c"],"versions":[{"version":"7.2","status":"affected"},{"version":"0","lessThan":"7.2","status":"unaffected","versionType":"semver"},{"version":"7.2.13","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2","versionEndExcluding":"7.3"}]}]}],"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()","x_generator":{"engine":"bippy-1.2.0"}}}}