{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47448 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47448 is a high-severity denial of service vulnerability in Linux kernel, published on 22 May 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-2021-47448 and fix it if it is affected.\n\nWhat it is: CVE-2021-47448 is a high-severity denial of service vulnerability in Linux kernel, published on 22 May 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-2021-47448 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-2021-47448/ (Markdown: https://insights.sbomify.com/CVE-2021-47448/index.md)","id":"CVE-2021-47448","markdown":"https://insights.sbomify.com/CVE-2021-47448/index.md","name":"CVE-2021-47448","record":{"aliases":["DEBIAN-CVE-2021-47448","GHSA-qh22-5q6m-7h2p","ROOT-OS-DEBIAN-11-CVE-2021-47448","UBUNTU-CVE-2021-47448"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel","requires_auth":"none","summary":"A local attacker can cause a system hang or crash by triggering an infinite loop in the MPTCP recvmsg function.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-835","name":"Loop with Unreachable Exit Condition"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix possible stall on recvmsg()\n\nrecvmsg() can enter an infinite loop if the caller provides the\nMSG_WAITALL, the data present in the receive queue is not sufficient to\nfulfill the request, and no more data is received by the peer.\n\nWhen the above happens, mptcp_wait_data() will always return with\nno wait, as the MPTCP_DATA_READY flag checked by such function is\nset and never cleared in such code path.\n\nLeveraging the above syzbot was able to trigger an RCU stall:\n\nrcu: INFO: rcu_preempt self-detected stall on CPU\nrcu:    0-...!: (10499 ticks this GP) idle=0af/1/0x4000000000000000 softirq=10678/10678 fqs=1\n        (t=10500 jiffies g=13089 q=109)\nrcu: rcu_preempt kthread starved for 10497 jiffies! g13089 f0x0 RCU_GP_WAIT_FQS(5) -\u003estate=0x0 -\u003ecpu=1\nrcu:    Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.\nrcu: RCU grace-period kthread stack dump:\ntask:rcu_preempt     state:R  running task     stack:28696 pid:   14 ppid:     2 flags:0x00004000\nCall Trace:\n context_switch kernel/sched/core.c:4955 [inline]\n __schedule+0x940/0x26f0 kernel/sched/core.c:6236\n schedule+0xd3/0x270 kernel/sched/core.c:6315\n schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881\n rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955\n rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128\n kthread+0x405/0x4f0 kernel/kthread.c:327\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295\nrcu: Stack dump where RCU GP kthread last ran:\nSending NMI from CPU 0 to CPUs 1:\nNMI backtrace for cpu 1\nCPU: 1 PID: 8510 Comm: syz-executor827 Not tainted 5.15.0-rc2-next-20210920-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nRIP: 0010:bytes_is_nonzero mm/kasan/generic.c:84 [inline]\nRIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]\nRIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]\nRIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]\nRIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]\nRIP: 0010:kasan_check_range+0xc8/0x180 mm/kasan/generic.c:189\nCode: 38 00 74 ed 48 8d 50 08 eb 09 48 83 c0 01 48 39 d0 74 7a 80 38 00 74 f2 48 89 c2 b8 01 00 00 00 48 85 d2 75 56 5b 5d 41 5c c3 \u003c48\u003e 85 d2 74 5e 48 01 ea eb 09 48 83 c0 01 48 39 d0 74 50 80 38 00\nRSP: 0018:ffffc9000cd676c8 EFLAGS: 00000283\nRAX: ffffed100e9a110e RBX: ffffed100e9a110f RCX: ffffffff88ea062a\nRDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff888074d08870\nRBP: ffffed100e9a110e R08: 0000000000000001 R09: ffff888074d08877\nR10: ffffed100e9a110e R11: 0000000000000000 R12: ffff888074d08000\nR13: ffff888074d08000 R14: ffff888074d08088 R15: ffff888074d08000\nFS:  0000555556d8e300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000\nS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000020000180 CR3: 0000000068909000 CR4: 00000000001506e0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n instrument_atomic_read_write include/linux/instrumented.h:101 [inline]\n test_and_clear_bit include/asm-generic/bitops/instrumented-atomic.h:83 [inline]\n mptcp_release_cb+0x14a/0x210 net/mptcp/protocol.c:3016\n release_sock+0xb4/0x1b0 net/core/sock.c:3204\n mptcp_wait_data net/mptcp/protocol.c:1770 [inline]\n mptcp_recvmsg+0xfd1/0x27b0 net/mptcp/protocol.c:2080\n inet6_recvmsg+0x11b/0x5e0 net/ipv6/af_inet6.c:659\n sock_recvmsg_nosec net/socket.c:944 [inline]\n ____sys_recvmsg+0x527/0x600 net/socket.c:2626\n ___sys_recvmsg+0x127/0x200 net/socket.c:2670\n do_recvmmsg+0x24d/0x6d0 net/socket.c:2764\n __sys_recvmmsg net/socket.c:2843 [inline]\n __do_sys_recvmmsg net/socket.c:2866 [inline]\n __se_sys_recvmmsg net/socket.c:2859 [inline]\n __x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2859\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\nRIP: 0033:0x7fc200d2\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":"mptcp: fix possible stall on recvmsg()","id":"CVE-2021-47448","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"ice: fix locking for Tx timestamp tracking flush","id":"CVE-2021-47449"},"packages":[],"prev":{"headline":"drm/msm/a3xx: fix error handling in a3xx_gpu_init()","id":"CVE-2021-47447"},"products":["Linux"],"published":"2024-05-22","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":"A local attacker can cause a system hang or crash by triggering an infinite loop in the MPTCP recvmsg function.","url":"https://insights.sbomify.com/CVE-2021-47448/"}