{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47136 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47136 is a high-severity vulnerability in Linux kernel, published on 25 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-47136 and fix it if it is affected.\n\nWhat it is: CVE-2021-47136 is a high-severity vulnerability in Linux kernel, published on 25 Mar 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-47136 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-2021-47136/ (Markdown: https://insights.sbomify.com/CVE-2021-47136/index.md)","id":"CVE-2021-47136","markdown":"https://insights.sbomify.com/CVE-2021-47136/index.md","name":"CVE-2021-47136","record":{"aliases":["DEBIAN-CVE-2021-47136","GHSA-7cg4-mp48-cggr","UBUNTU-CVE-2021-47136"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel","requires_auth":"none","summary":"An attacker can read uninitialized kernel memory via the network stack, potentially exposing sensitive data.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":8.6,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H","version":"3.1"},"cwes":[{"id":"CWE-908","name":"Use of Uninitialized Resource"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: zero-initialize tc skb extension on allocation\n\nFunction skb_ext_add() doesn't initialize created skb extension with any\nvalue and leaves it up to the user. However, since extension of type\nTC_SKB_EXT originally contained only single value tc_skb_ext-\u003echain its\nusers used to just assign the chain value without setting whole extension\nmemory to zero first. This assumption changed when TC_SKB_EXT extension was\nextended with additional fields but not all users were updated to\ninitialize the new fields which leads to use of uninitialized memory\nafterwards. UBSAN log:\n\n[  778.299821] UBSAN: invalid-load in net/openvswitch/flow.c:899:28\n[  778.301495] load of value 107 is not a valid value for type '_Bool'\n[  778.303215] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.12.0-rc7+ #2\n[  778.304933] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014\n[  778.307901] Call Trace:\n[  778.308680]  \u003cIRQ\u003e\n[  778.309358]  dump_stack+0xbb/0x107\n[  778.310307]  ubsan_epilogue+0x5/0x40\n[  778.311167]  __ubsan_handle_load_invalid_value.cold+0x43/0x48\n[  778.312454]  ? memset+0x20/0x40\n[  778.313230]  ovs_flow_key_extract.cold+0xf/0x14 [openvswitch]\n[  778.314532]  ovs_vport_receive+0x19e/0x2e0 [openvswitch]\n[  778.315749]  ? ovs_vport_find_upcall_portid+0x330/0x330 [openvswitch]\n[  778.317188]  ? create_prof_cpu_mask+0x20/0x20\n[  778.318220]  ? arch_stack_walk+0x82/0xf0\n[  778.319153]  ? secondary_startup_64_no_verify+0xb0/0xbb\n[  778.320399]  ? stack_trace_save+0x91/0xc0\n[  778.321362]  ? stack_trace_consume_entry+0x160/0x160\n[  778.322517]  ? lock_release+0x52e/0x760\n[  778.323444]  netdev_frame_hook+0x323/0x610 [openvswitch]\n[  778.324668]  ? ovs_netdev_get_vport+0xe0/0xe0 [openvswitch]\n[  778.325950]  __netif_receive_skb_core+0x771/0x2db0\n[  778.327067]  ? lock_downgrade+0x6e0/0x6f0\n[  778.328021]  ? lock_acquire+0x565/0x720\n[  778.328940]  ? generic_xdp_tx+0x4f0/0x4f0\n[  778.329902]  ? inet_gro_receive+0x2a7/0x10a0\n[  778.330914]  ? lock_downgrade+0x6f0/0x6f0\n[  778.331867]  ? udp4_gro_receive+0x4c4/0x13e0\n[  778.332876]  ? lock_release+0x52e/0x760\n[  778.333808]  ? dev_gro_receive+0xcc8/0x2380\n[  778.334810]  ? lock_downgrade+0x6f0/0x6f0\n[  778.335769]  __netif_receive_skb_list_core+0x295/0x820\n[  778.336955]  ? process_backlog+0x780/0x780\n[  778.337941]  ? mlx5e_rep_tc_netdevice_event_unregister+0x20/0x20 [mlx5_core]\n[  778.339613]  ? seqcount_lockdep_reader_access.constprop.0+0xa7/0xc0\n[  778.341033]  ? kvm_clock_get_cycles+0x14/0x20\n[  778.342072]  netif_receive_skb_list_internal+0x5f5/0xcb0\n[  778.343288]  ? __kasan_kmalloc+0x7a/0x90\n[  778.344234]  ? mlx5e_handle_rx_cqe_mpwrq+0x9e0/0x9e0 [mlx5_core]\n[  778.345676]  ? mlx5e_xmit_xdp_frame_mpwqe+0x14d0/0x14d0 [mlx5_core]\n[  778.347140]  ? __netif_receive_skb_list_core+0x820/0x820\n[  778.348351]  ? mlx5e_post_rx_mpwqes+0xa6/0x25d0 [mlx5_core]\n[  778.349688]  ? napi_gro_flush+0x26c/0x3c0\n[  778.350641]  napi_complete_done+0x188/0x6b0\n[  778.351627]  mlx5e_napi_poll+0x373/0x1b80 [mlx5_core]\n[  778.352853]  __napi_poll+0x9f/0x510\n[  778.353704]  ? mlx5_flow_namespace_set_mode+0x260/0x260 [mlx5_core]\n[  778.355158]  net_rx_action+0x34c/0xa40\n[  778.356060]  ? napi_threaded_poll+0x3d0/0x3d0\n[  778.357083]  ? sched_clock_cpu+0x18/0x190\n[  778.358041]  ? __common_interrupt+0x8e/0x1a0\n[  778.359045]  __do_softirq+0x1ce/0x984\n[  778.359938]  __irq_exit_rcu+0x137/0x1d0\n[  778.360865]  irq_exit_rcu+0xa/0x20\n[  778.361708]  common_interrupt+0x80/0xa0\n[  778.362640]  \u003c/IRQ\u003e\n[  778.363212]  asm_common_interrupt+0x1e/0x40\n[  778.364204] RIP: 0010:native_safe_halt+0xe/0x10\n[  778.365273] Code: 4f ff ff ff 4c 89 e7 e8 50 3f 40 fe e9 dc fe ff ff 48 89 df e8 43 3f 40 fe eb 90 cc e9 07 00 00 00 0f 00 2d 74 05 62 00 fb f4 \u003cc3\u003e 90 e9 07 00 00 00 0f 00 2d 64 05 62 00 f4 c3 cc cc 0f 1f 44 00\n[  778.369355] RSP: 0018:ffffffff84407e48 EFLAGS: 00000246\n[  778.370570] RAX\n---truncated---","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: zero-initialize tc skb extension on allocation","id":"CVE-2021-47136","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"information_disclosure","year":"2021"},"n_packages":0,"n_references":3,"next":{"headline":"net: lantiq: fix memory corruption in RX ring","id":"CVE-2021-47137"},"packages":[],"prev":{"headline":"mt76: mt7921: fix possible AOOB issue in mt7921_mcu_tx_rate_report","id":"CVE-2021-47135"},"products":["Linux"],"published":"2024-03-25","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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"An attacker can read uninitialized kernel memory via the network stack, potentially exposing sensitive data.","url":"https://insights.sbomify.com/CVE-2021-47136/"}