{"api_version":"1","generated_at":"2026-08-09T05:11:21+00:00","cve":"CVE-2026-64566","urls":{"html":"https://cve.report/CVE-2026-64566","api":"https://cve.report/api/cve/CVE-2026-64566.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64566","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64566"},"summary":{"title":"xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()\n\nWhen iptfs_skb_add_frags() copies frag references from the source\nfrag walk into a new SKB, it increments the page reference count via\n__skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the\ndestination SKB's skb_shinfo->flags.\n\nIf the source SKB carries shared frags (e.g. from a page-pool backed\nreceive path), the new inner SKB will appear to ESP as having privately\nowned frags.  A subsequent esp_input() call for a nested transport-mode\nSA then takes the no-COW fast path and decrypts in place, writing over\npages that are still referenced by the outer IPTFS SKB.  This causes\nkernel-visible memory corruption and can trigger a panic.\n\nAll other frag-transfer helpers in the kernel (skb_try_coalesce,\nskb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly\npropagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this\nconvention by setting the flag inside the loop immediately after\n__skb_frag_ref() and nr_frags++, so every exit path that attaches a frag\nunconditionally propagates SKBFL_SHARED_FRAG.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-05 08:16:36","updated_at":"2026-08-08 15:16:31"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/430ea57d6daf765e88f90046afbfd1e071cb7200","name":"https://git.kernel.org/stable/c/430ea57d6daf765e88f90046afbfd1e071cb7200","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0","name":"https://git.kernel.org/stable/c/ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d8aaf06b29f5a0b6186cf68d21c7d63678ee3891","name":"https://git.kernel.org/stable/c/d8aaf06b29f5a0b6186cf68d21c7d63678ee3891","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64566","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64566","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 d8aaf06b29f5a0b6186cf68d21c7d63678ee3891 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7 430ea57d6daf765e88f90046afbfd1e071cb7200 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.14","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.14 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.42 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.6 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc4 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64566","cve":"CVE-2026-64566","epss":"0.001540000","percentile":"0.050920000","score_date":"2026-08-08","updated_at":"2026-08-09 00:07:22"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/xfrm/xfrm_iptfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"d8aaf06b29f5a0b6186cf68d21c7d63678ee3891","status":"affected","version":"5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7","versionType":"git"},{"lessThan":"ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0","status":"affected","version":"5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7","versionType":"git"},{"lessThan":"430ea57d6daf765e88f90046afbfd1e071cb7200","status":"affected","version":"5f2b6a9095743a6bf1f34c43c4fe78fa8bdf5ad7","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/xfrm/xfrm_iptfs.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.14"},{"lessThan":"6.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.42","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.6","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc4","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.42","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.6","versionStartIncluding":"6.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc4","versionStartIncluding":"6.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()\n\nWhen iptfs_skb_add_frags() copies frag references from the source\nfrag walk into a new SKB, it increments the page reference count via\n__skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the\ndestination SKB's skb_shinfo->flags.\n\nIf the source SKB carries shared frags (e.g. from a page-pool backed\nreceive path), the new inner SKB will appear to ESP as having privately\nowned frags.  A subsequent esp_input() call for a nested transport-mode\nSA then takes the no-COW fast path and decrypts in place, writing over\npages that are still referenced by the outer IPTFS SKB.  This causes\nkernel-visible memory corruption and can trigger a panic.\n\nAll other frag-transfer helpers in the kernel (skb_try_coalesce,\nskb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly\npropagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this\nconvention by setting the flag inside the loop immediately after\n__skb_frag_ref() and nr_frags++, so every exit path that attaches a frag\nunconditionally propagates SKBFL_SHARED_FRAG."}],"metrics":[{"cvssV3_1":{"baseScore":9.8,"baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - The flaw is on the IPsec IPTFS receive path: inbound ESP packets hit xfrm_input → iptfs_input → iptfs_skb_add_frags, then reinjected inner packets reach nested transport-mode esp_input(); a remote IPTFS/IPsec peer triggers it with network packets.\nAC:L - On a host with IPTFS plus a nested transport-mode SA, the peer fully controls packet sizes and ESP payloads that take the frag-share path and drive in-place decrypt; no race or attacker-uncontrollable memory layout is required.\nPR:N - Exploitation is by a remote IPsec peer sending packets to an already-configured IPTFS endpoint; no local account or capability on the target is required, and SA presence is a deployment precondition rather than an attacker privilege.\nUI:N - Packets are processed in softirq/NAPI receive context with no victim action such as mounting, opening a file, or otherwise interacting with the system.\nS:U - Corruption is of shared skb/NIC fragment pages within the same kernel security authority; this is not a VM escape, IOMMU bypass, or cross-sandbox boundary crossing.\nC:H - Missing SKBFL_SHARED_FRAG lets nested esp_input() overwrite pages still referenced by the outer IPTFS skb and sibling inners, yielding attacker-influenced memory corruption that can be leveraged for information disclosure.\nI:H - In-place ESP decryption writes attacker-controlled plaintext into pages still held by other skbs, providing a memory-corruption write primitive capable of integrity compromise and control-flow impact.\nA:H - The same shared-page overwrite causes kernel-visible memory corruption and can panic/oops the host, fully denying availability."}]}],"providerMetadata":{"dateUpdated":"2026-08-08T15:13:07.286Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/d8aaf06b29f5a0b6186cf68d21c7d63678ee3891"},{"url":"https://git.kernel.org/stable/c/ffd64e0717efd83fbf3396ab4e5ac6d795dac4d0"},{"url":"https://git.kernel.org/stable/c/430ea57d6daf765e88f90046afbfd1e071cb7200"}],"title":"xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64566","datePublished":"2026-08-05T08:06:18.645Z","dateReserved":"2026-07-19T15:36:31.797Z","dateUpdated":"2026-08-08T15:13:07.286Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-05 08:16:36","lastModifiedDate":"2026-08-08 15:16:31","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64566","Ordinal":"1","Title":"xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags(","CVE":"CVE-2026-64566","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64566","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()\n\nWhen iptfs_skb_add_frags() copies frag references from the source\nfrag walk into a new SKB, it increments the page reference count via\n__skb_frag_ref() but does not propagate SKBFL_SHARED_FRAG to the\ndestination SKB's skb_shinfo->flags.\n\nIf the source SKB carries shared frags (e.g. from a page-pool backed\nreceive path), the new inner SKB will appear to ESP as having privately\nowned frags.  A subsequent esp_input() call for a nested transport-mode\nSA then takes the no-COW fast path and decrypts in place, writing over\npages that are still referenced by the outer IPTFS SKB.  This causes\nkernel-visible memory corruption and can trigger a panic.\n\nAll other frag-transfer helpers in the kernel (skb_try_coalesce,\nskb_gro_receive, __pskb_copy_fclone, skb_shift, skb_segment) correctly\npropagate SKBFL_SHARED_FRAG; align iptfs_skb_add_frags() with this\nconvention by setting the flag inside the loop immediately after\n__skb_frag_ref() and nr_frags++, so every exit path that attaches a frag\nunconditionally propagates SKBFL_SHARED_FRAG.","Type":"Description","Title":"xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags("}]}}}