CVE-2026-64061 (GCVE-0-2026-64061)
Vulnerability from cvelistv5
Published
2026-07-19 15:39
Modified
2026-08-05 12:38
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: netfs: Fix early put of sink folio in netfs_read_gaps() Fix netfs_read_gaps() to release the sink page it uses after waiting for the request to complete. The way the sink page is used is that an ITER_BVEC-class iterator is created that has the gaps from the target folio at either end, but has the sink page tiled over the middle so that a single read op can fill in both gaps. The bug was found by KASAN detecting a UAF on the generic/075 xfstest in the cifsd kernel thread that handles reception of data from the TCP socket: BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20 Write of size 885 at addr ffff888107f92000 by task cifsd/1285 CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy) Call Trace: dump_stack_lvl+0x5d/0x80 print_report+0x17f/0x4f1 kasan_report+0x100/0x1e0 kasan_check_range+0x10f/0x1e0 __asan_memcpy+0x3c/0x60 _copy_to_iter+0x48a/0xa20 __skb_datagram_iter+0x2c9/0x430 skb_copy_datagram_iter+0x6e/0x160 tcp_recvmsg_locked+0xce0/0x1130 tcp_recvmsg+0xeb/0x300 inet_recvmsg+0xcf/0x3a0 sock_recvmsg+0xea/0x100 cifs_readv_from_socket+0x3a6/0x4d0 [cifs] cifs_read_iter_from_socket+0xdd/0x130 [cifs] cifs_readv_receive+0xaad/0xb10 [cifs] cifs_demultiplex_thread+0x1148/0x1740 [cifs] kthread+0x1cf/0x210
References
Impacted products
Vendor Product Version
Linux Linux Version: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e
Version: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e
Version: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e
Version: ee4cdf7ba857a894ad1650d6ab77669cbbfa329e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/buffered_read.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2a39d49c8d97df8cb8fa80c10859bc1ba7358c6b",
              "status": "affected",
              "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e",
              "versionType": "git"
            },
            {
              "lessThan": "d4f4bc87c76511cf2532448b0fa40c25e894bd7d",
              "status": "affected",
              "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e",
              "versionType": "git"
            },
            {
              "lessThan": "412e8bad48967fd34295866636c028befd27d8b9",
              "status": "affected",
              "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e",
              "versionType": "git"
            },
            {
              "lessThan": "3e5dd91b87a8b1450217b56a336bee315f40da7d",
              "status": "affected",
              "version": "ee4cdf7ba857a894ad1650d6ab77669cbbfa329e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/netfs/buffered_read.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.92",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfs: Fix early put of sink folio in netfs_read_gaps()\n\nFix netfs_read_gaps() to release the sink page it uses after waiting for\nthe request to complete.  The way the sink page is used is that an\nITER_BVEC-class iterator is created that has the gaps from the target folio\nat either end, but has the sink page tiled over the middle so that a single\nread op can fill in both gaps.\n\nThe bug was found by KASAN detecting a UAF on the generic/075 xfstest in\nthe cifsd kernel thread that handles reception of data from the TCP socket:\n\n BUG: KASAN: use-after-free in _copy_to_iter+0x48a/0xa20\n Write of size 885 at addr ffff888107f92000 by task cifsd/1285\n CPU: 2 UID: 0 PID: 1285 Comm: cifsd Not tainted 7.0.0 #6 PREEMPT(lazy)\n Call Trace:\n  dump_stack_lvl+0x5d/0x80\n  print_report+0x17f/0x4f1\n  kasan_report+0x100/0x1e0\n  kasan_check_range+0x10f/0x1e0\n  __asan_memcpy+0x3c/0x60\n  _copy_to_iter+0x48a/0xa20\n  __skb_datagram_iter+0x2c9/0x430\n  skb_copy_datagram_iter+0x6e/0x160\n  tcp_recvmsg_locked+0xce0/0x1130\n  tcp_recvmsg+0xeb/0x300\n  inet_recvmsg+0xcf/0x3a0\n  sock_recvmsg+0xea/0x100\n  cifs_readv_from_socket+0x3a6/0x4d0 [cifs]\n  cifs_read_iter_from_socket+0xdd/0x130 [cifs]\n  cifs_readv_receive+0xaad/0xb10 [cifs]\n  cifs_demultiplex_thread+0x1148/0x1740 [cifs]\n  kthread+0x1cf/0x210"
        }
      ],
      "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 UAF write occurs in the CIFS client kernel thread while copying SMB read-response data received over TCP; a compromised or malicious network filesystem server can supply attacker-controlled payload once a client performs normal buffered read/write on a mounted share.\nAC:L - The bug is deterministic\u2014folio_put(sink) always runs before netfs_wait_for_read() completes\u2014so an attacker who can create a dirty streaming-write folio and then read it reliably triggers the UAF without winning a race.\nPR:N - A remote malicious/compromised SMB/NFS/9p/Ceph server attacker needs no local privileges on the victim; exploitation requires only ordinary file access on an existing network mount, not root or special capabilities.\nUI:N - No special victim interaction beyond normal file read/write operations on a mounted network filesystem; persistent automounts and server-driven workloads make mount-time interaction unnecessary for exploitation.\nS:U - Impact is kernel heap memory corruption within the same kernel security domain; it does not cross VM, container, or IOMMU boundaries.\nC:H - Use-after-free of a page-cache folio enables heap grooming and arbitrary kernel memory read primitives; UAF class bugs are scored High for confidentiality per kernel CNA guidance.\nI:H - The UAF is a write primitive\u2014KASAN reported an 885-byte write of network-supplied data into freed memory\u2014enabling controlled heap corruption and potential code execution.\nA:H - UAF during network I/O can cause kernel oops/panic and denial of service to all workloads on the host; UAF bugs are scored High for availability per kernel CNA guidance."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:38:49.000Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2a39d49c8d97df8cb8fa80c10859bc1ba7358c6b"
        },
        {
          "url": "https://git.kernel.org/stable/c/d4f4bc87c76511cf2532448b0fa40c25e894bd7d"
        },
        {
          "url": "https://git.kernel.org/stable/c/412e8bad48967fd34295866636c028befd27d8b9"
        },
        {
          "url": "https://git.kernel.org/stable/c/3e5dd91b87a8b1450217b56a336bee315f40da7d"
        }
      ],
      "title": "netfs: Fix early put of sink folio in netfs_read_gaps()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64061",
    "datePublished": "2026-07-19T15:39:40.913Z",
    "dateReserved": "2026-07-19T07:54:57.030Z",
    "dateUpdated": "2026-08-05T12:38:49.000Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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