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      }
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        "category": "legal_disclaimer",
        "text": "This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Cloud Linux Inc. and provide a link to the original.",
        "title": "Terms of Use"
      }
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        "url": "https://security.tuxcare.com/csaf/v2/els_os/ubuntu18.04els/vex/2025/cve-2025-21653-els_os-ubuntu18_04els.json"
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    ],
    "title": "Security update on CVE-2025-21653",
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          "number": "1",
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          "date": "2025-06-10T09:45:36Z",
          "number": "2",
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        {
          "date": "2025-12-23T22:15:38Z",
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  "vulnerabilities": [
    {
      "cve": "CVE-2025-21653",
      "cwe": {
        "id": "CWE-20",
        "name": "Improper Input Validation"
      },
      "notes": [
        {
          "category": "description",
          "text": "In the Linux kernel, the following vulnerability has been resolved:\nnet_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute\nsyzbot found that TCA_FLOW_RSHIFT attribute was not validated.\nRight shitfing a 32bit integer is undefined for large shift values.\nUBSAN: shift-out-of-bounds in net/sched/cls_flow.c:329:23\nshift exponent 9445 is too large for 32-bit type 'u32' (aka 'unsigned int')\nCPU: 1 UID: 0 PID: 54 Comm: kworker/u8:3 Not tainted 6.13.0-rc3-syzkaller-00180-g4f619d518db9 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\nWorkqueue: ipv6_addrconf addrconf_dad_work\nCall Trace:\n<TASK>\n__dump_stack lib/dump_stack.c:94 [inline]\ndump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\nubsan_epilogue lib/ubsan.c:231 [inline]\n__ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468\nflow_classify+0x24d5/0x25b0 net/sched/cls_flow.c:329\ntc_classify include/net/tc_wrapper.h:197 [inline]\n__tcf_classify net/sched/cls_api.c:1771 [inline]\ntcf_classify+0x420/0x1160 net/sched/cls_api.c:1867\nsfb_classify net/sched/sch_sfb.c:260 [inline]\nsfb_enqueue+0x3ad/0x18b0 net/sched/sch_sfb.c:318\ndev_qdisc_enqueue+0x4b/0x290 net/core/dev.c:3793\n__dev_xmit_skb net/core/dev.c:3889 [inline]\n__dev_queue_xmit+0xf0e/0x3f50 net/core/dev.c:4400\ndev_queue_xmit include/linux/netdevice.h:3168 [inline]\nneigh_hh_output include/net/neighbour.h:523 [inline]\nneigh_output include/net/neighbour.h:537 [inline]\nip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236\niptunnel_xmit+0x55d/0x9b0 net/ipv4/ip_tunnel_core.c:82\nudp_tunnel_xmit_skb+0x262/0x3b0 net/ipv4/udp_tunnel_core.c:173\ngeneve_xmit_skb drivers/net/geneve.c:916 [inline]\ngeneve_xmit+0x21dc/0x2d00 drivers/net/geneve.c:1039\n__netdev_start_xmit include/linux/netdevice.h:5002 [inline]\nnetdev_start_xmit include/linux/netdevice.h:5011 [inline]\nxmit_one net/core/dev.c:3590 [inline]\ndev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606\n__dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434",
          "title": "Vulnerability description"
        },
        {
          "category": "general",
          "text": "The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.",
          "title": "CVSS score applicability"
        }
      ],
      "product_status": {
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          "category": "self",
          "summary": "Canonical URL",
          "url": "https://cve.tuxcare.com/els/cve/CVE-2025-21653"
        }
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      "scores": [
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            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 4.7,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
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