{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21653 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21653 is a medium-severity vulnerability in Linux kernel, published on 19 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-21653 and fix it if it is affected.\n\nWhat it is: CVE-2025-21653 is a medium-severity vulnerability in Linux kernel, published on 19 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-21653 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-21653/ (Markdown: https://insights.sbomify.com/CVE-2025-21653/index.md)","id":"CVE-2025-21653","markdown":"https://insights.sbomify.com/CVE-2025-21653/index.md","name":"CVE-2025-21653","record":{"aliases":["BELL-CVE-2025-21653","DEBIAN-CVE-2025-21653","GHSA-478m-w5gm-f3cr","UBUNTU-CVE-2025-21653"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A missing validation in the Linux kernel's cls_flow scheduler allows a large shift value to cause an undefined behavior, potentially leading to a system crash.","user_interaction":"not_required","vuln_class":"integer_overflow"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute\n\nsyzbot found that TCA_FLOW_RSHIFT attribute was not validated.\nRight shitfing a 32bit integer is undefined for large shift values.\n\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 \u003cTASK\u003e\n  __dump_stack lib/dump_stack.c:94 [inline]\n  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120\n  ubsan_epilogue lib/ubsan.c:231 [inline]\n  __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468\n  flow_classify+0x24d5/0x25b0 net/sched/cls_flow.c:329\n  tc_classify include/net/tc_wrapper.h:197 [inline]\n  __tcf_classify net/sched/cls_api.c:1771 [inline]\n  tcf_classify+0x420/0x1160 net/sched/cls_api.c:1867\n  sfb_classify net/sched/sch_sfb.c:260 [inline]\n  sfb_enqueue+0x3ad/0x18b0 net/sched/sch_sfb.c:318\n  dev_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\n  dev_queue_xmit include/linux/netdevice.h:3168 [inline]\n  neigh_hh_output include/net/neighbour.h:523 [inline]\n  neigh_output include/net/neighbour.h:537 [inline]\n  ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236\n  iptunnel_xmit+0x55d/0x9b0 net/ipv4/ip_tunnel_core.c:82\n  udp_tunnel_xmit_skb+0x262/0x3b0 net/ipv4/udp_tunnel_core.c:173\n  geneve_xmit_skb drivers/net/geneve.c:916 [inline]\n  geneve_xmit+0x21dc/0x2d00 drivers/net/geneve.c:1039\n  __netdev_start_xmit include/linux/netdevice.h:5002 [inline]\n  netdev_start_xmit include/linux/netdevice.h:5011 [inline]\n  xmit_one net/core/dev.c:3590 [inline]\n  dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606\n  __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute","id":"CVE-2025-21653","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"integer_overflow","year":"2025"},"n_packages":0,"n_references":7,"next":{"headline":"ovl: support encoding fid from inode with no alias","id":"CVE-2025-21654"},"packages":[],"prev":{"headline":"ipvlan: Fix use-after-free in ipvlan_get_iflink().","id":"CVE-2025-21652"},"products":["Linux"],"published":"2025-01-19","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-15","vendors":["Linux"]},"summary":"A missing validation in the Linux kernel's cls_flow scheduler allows a large shift value to cause an undefined behavior, potentially leading to a system crash.","url":"https://insights.sbomify.com/CVE-2025-21653/"}