{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/esp4.c",
            "net/ipv6/esp6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cb375965800d474c0281a2e92c43c724fce9f463",
              "status": "affected",
              "version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
              "versionType": "git"
            },
            {
              "lessThan": "201bdf10ae92e7cbd524adf8c0323e2a963d5fd7",
              "status": "affected",
              "version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
              "versionType": "git"
            },
            {
              "lessThan": "3ec55f0c8a6a543cf660584d1346e11f6311ee59",
              "status": "affected",
              "version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
              "versionType": "git"
            },
            {
              "lessThan": "1ad6456898f6e6cf58be83bdb607acb1119a9cd1",
              "status": "affected",
              "version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
              "versionType": "git"
            },
            {
              "lessThan": "26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf",
              "status": "affected",
              "version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
              "versionType": "git"
            },
            {
              "lessThan": "21697720ff43b8dfa25b8e8d9ca7f56f4597fc80",
              "status": "affected",
              "version": "cac2661c53f35cbe651bef9b07026a5a05ab8ce0",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv4/esp4.c",
            "net/ipv6/esp6.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.11"
            },
            {
              "lessThan": "4.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.57",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.191",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.57",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "4.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nesp: do not unref managed frag pages in esp_ssg_unref()\n\nesp_ssg_unref() releases the page references held on the source\nscatterlist after the AEAD operation completes.  It calls\nskb_page_unref() on every frag page for an out-of-place transform\n(req-\u003esrc != req-\u003edst), and in the error path of esp_output_tail()\n(already_unref == true) on the request\u0027s own scatterlist.\n\nThis is wrong when the skb carries managed frags\n(SKBFL_MANAGED_FRAG_REFS).  Managed frags are owned by a zerocopy ubuf\nand the skb does not hold a per-frag page reference; io_uring SEND_ZC\nwith a registered buffer attaches the bvec pages this way via\nio_sg_from_iter().  The rest of the stack honours this invariant:\nskb_release_data() skips the per-frag unref when SKBFL_MANAGED_FRAG_REFS\nis set, and skb_zcopy_managed() is the guard used at the other unref\nsites.\n\nesp_ssg_unref() is missing that guard, so for a managed-frag skb it\ndrops a page reference the skb never acquired.  This can underflow the\npage reference count and free a page that is still in use.\n\nGuard the function with skb_zcopy_managed() so both unref paths are\nskipped for managed-frag skbs, matching skb_release_data()."
        }
      ],
      "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 - The extra unref is reached from IORING_OP_SEND_ZC/SENDMSG_ZC with IORING_RECVSEND_FIXED_BUF: io_sendmsg_zc() -\u003e sock_sendmsg() -\u003e tcp_sendmsg_locked() -\u003e xfrm_output() -\u003e esp_output_tail() -\u003e esp_ssg_unref(). io_sg_from_iter() is the only site that sets SKBFL_MANAGED_FRAG_REFS; esp_input() never calls esp_ssg_unref(), so a remote ESP packet cannot supply the buggy skb.\nAC:L - tcp_stream_alloc_skb() allocates MAX_TCP_HEADER then skb_reserve()s all of it, so a SEND_ZC TCP skb has ~0 tailroom. esp_output_head() therefore takes inplace=false (tailen \u003e tailroom, nr_frags \u003c MAX_SKB_FRAGS, data_len+tailen \u003c= PAGE_SIZE), after which esp_output_tail() replaces the frags and esp_ssg_unref() always drops the managed pages. The attacker chooses the send size.\nPR:L - io_uring_setup() allows IORING_OP_SEND_ZC when sysctl_io_uring_disabled==0 (default); no capability is checked on that send path. An ESP SA is also required: the attacker can add one in a user+net namespace because xfrm_user_rcv_msg() only tests netlink_net_capable(CAP_NET_ADMIN) against the netns user_ns, or can send through an already-installed IPsec policy.\nUI:N - The attacker registers the buffer with IORING_REGISTER_BUFFERS, submits SEND_ZC, and if needed installs the XFRM state/policy; no other user must open a file, mount a volume, or otherwise act.\nS:U - esp_ssg_unref()\u0027s extra put_page() corrupts host kernel page refcounts. That is a conventional local privilege escalation inside the same kernel, not a KVM/Xen guest-to-host or IOMMU-scope change.\nC:H - After the out-of-place transform, esp_ssg_unref() calls skb_page_unref() on every source sg page past skb-\u003edata. Those pages were attached by io_sg_from_iter() without a per-frag get_page(), so the extra put underflows the refcount of still-mapped IORING_REGISTER_BUFFERS pages and frees memory the attacker can read.\nI:H - The same extra skb_page_unref() frees registered-buffer pages that remain in the io_uring bvec and the attacker\u0027s userspace mapping, so the page can be reallocated and overwritten, giving an arbitrary write and control-flow hijack.\nA:H - The extra put_page() on managed frag pages underflows the page refcount and frees a page still in use, which oopses with bad page state even when the use-after-free is not turned into a full memory-corruption exploit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:36:00.346Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/cb375965800d474c0281a2e92c43c724fce9f463"
        },
        {
          "url": "https://git.kernel.org/stable/c/201bdf10ae92e7cbd524adf8c0323e2a963d5fd7"
        },
        {
          "url": "https://git.kernel.org/stable/c/3ec55f0c8a6a543cf660584d1346e11f6311ee59"
        },
        {
          "url": "https://git.kernel.org/stable/c/1ad6456898f6e6cf58be83bdb607acb1119a9cd1"
        },
        {
          "url": "https://git.kernel.org/stable/c/26b6b14c7a0368e317a1e9fb5144ebe6f8d495cf"
        },
        {
          "url": "https://git.kernel.org/stable/c/21697720ff43b8dfa25b8e8d9ca7f56f4597fc80"
        }
      ],
      "title": "esp: do not unref managed frag pages in esp_ssg_unref()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93105",
    "datePublished": "2026-09-17T16:11:16.442Z",
    "dateReserved": "2026-09-17T16:02:15.085Z",
    "dateUpdated": "2026-10-30T12:36:00.346Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}