[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"repo-stars":3,"vuln-DEBIAN-CVE-2021-46936":6},{"stargazers_count":4,"fetched_at":5},7,"2026-06-04T08:53:30.047Z",{"id":7,"descriptions":8,"cisa":9,"weaknesses":10,"exploits":11,"aliases":12,"duplicate_of":9,"upstream":13,"downstream":16,"duplicates":17,"related":18,"reserved_at":9,"published_at":19,"modified_at":20,"state":9,"summary":21,"references_raw":23,"kevs":30,"epss":9,"epss_history":31,"metrics":32,"affected":39},"DEBIAN-CVE-2021-46936","In the Linux kernel, the following vulnerability has been resolved:  net: fix use-after-free in tw_timer_handler  A real world panic issue was found as follow in Linux 5.4.      BUG: unable to handle page fault for address: ffffde49a863de28     PGD 7e6fe62067 P4D 7e6fe62067 PUD 7e6fe63067 PMD f51e064067 PTE 0     RIP: 0010:tw_timer_handler+0x20/0x40     Call Trace:      \u003CIRQ>      call_timer_fn+0x2b/0x120      run_timer_softirq+0x1ef/0x450      __do_softirq+0x10d/0x2b8      irq_exit+0xc7/0xd0      smp_apic_timer_interrupt+0x68/0x120      apic_timer_interrupt+0xf/0x20  This issue was also reported since 2017 in the thread [1], unfortunately, the issue was still can be reproduced after fixing DCCP.  The ipv4_mib_exit_net is called before tcp_sk_exit_batch when a net namespace is destroyed since tcp_sk_ops is registered befrore ipv4_mib_ops, which means tcp_sk_ops is in the front of ipv4_mib_ops in the list of pernet_list. There will be a use-after-free on net->mib.net_statistics in tw_timer_handler after ipv4_mib_exit_net if there are some inflight time-wait timers.  This bug is not introduced by commit f2bf415cfed7 (\"mib: add net to NET_ADD_STATS_BH\") since the net_statistics is a global variable instead of dynamic allocation and freeing. Actually, commit 61a7e26028b9 (\"mib: put net statistics on struct net\") introduces the bug since it put net statistics on struct net and free it when net namespace is destroyed.  Moving init_ipv4_mibs() to the front of tcp_init() to fix this bug and replace pr_crit() with panic() since continuing is meaningless when init_ipv4_mibs() fails.  [1] https://groups.google.com/g/syzkaller/c/p1tn-_Kc6l4/m/smuL_FMAAgAJ?pli=1",null,[],[],[],[14],{"_key":15},"CVE-2021-46936",[],[],[],"2024-02-27T10:15:08.017Z","2026-04-28T20:23:16.084867Z",{"cisa_kev":22,"cisa_ransomware":22,"cisa_vendor":9,"epss_severity":9,"epss_score":9,"severity":9,"severity_score":9,"severity_version":9,"severity_source":9,"severity_vector":9,"severity_status":9},false,[24],{"url":25,"sources":26,"tags":28},"https://security-tracker.debian.org/tracker/CVE-2021-46936",[27],"osv_debian",[29],"Advisory",[],[],[33],{"source":27,"cvss_v2_0":9,"cvss_v3_0":9,"cvss_v3_1":34,"cvss_v4_0":9},{"baseScore":35,"baseSeverity":9,"vectorString":36,"impactScore":37,"exploitabilityScore":38},7.8,"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",9.8,4.6,[40],{"ecosystem":41,"name":42,"vendor":43,"product":42,"cpe_part":9,"purl_type":44,"purl_namespace":43,"purl_name":42,"source":9,"versions":45},"Debian","linux","debian","deb",[46,52,55,56],{"version":47,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":50,"version_end_type":51,"fixed_in":9},"lt5_10_92_1",true,"ecosystem","5.10.92-1","excluding",{"version":53,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":54,"version_end_type":51,"fixed_in":9},"lt5_15_15_1","5.15.15-1",{"version":53,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":54,"version_end_type":51,"fixed_in":9},{"version":53,"is_range":48,"range_type":49,"version_start":9,"version_start_type":9,"version_end":54,"version_end_type":51,"fixed_in":9}]