{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-22977 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-22977 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Jan 2026. 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-2026-22977 and fix it if it is affected.\n\nWhat it is: CVE-2026-22977 is a medium-severity denial of service vulnerability in Linux kernel, published on 21 Jan 2026. 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-2026-22977 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-2026-22977/ (Markdown: https://insights.sbomify.com/CVE-2026-22977/index.md)","id":"CVE-2026-22977","markdown":"https://insights.sbomify.com/CVE-2026-22977/index.md","name":"CVE-2026-22977","record":{"aliases":["AZL-78449","BELL-CVE-2026-22977","DEBIAN-CVE-2026-22977","GHSA-rgj2-xq4c-hrvm","ROOT-OS-DEBIAN-11-CVE-2026-22977","ROOT-OS-DEBIAN-12-CVE-2026-22977","ROOT-OS-DEBIAN-13-CVE-2026-22977","ROOT-OS-UBUNTU-2204-CVE-2026-22977","ROOT-OS-UBUNTU-2404-CVE-2026-22977","UBUNTU-CVE-2026-22977"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A missing usercopy whitelist in the Linux kernel causes a panic when reading socket error queues, leading to denial of service.","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":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":[{"id":"CWE-476","name":"NULL Pointer Dereference"},{"id":"CWE-400","name":"Uncontrolled Resource Consumption"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: sock: fix hardened usercopy panic in sock_recv_errqueue\n\nskbuff_fclone_cache was created without defining a usercopy region,\n[1] unlike skbuff_head_cache which properly whitelists the cb[] field.\n[2] This causes a usercopy BUG() when CONFIG_HARDENED_USERCOPY is\nenabled and the kernel attempts to copy sk_buff.cb data to userspace\nvia sock_recv_errqueue() -\u003e put_cmsg().\n\nThe crash occurs when: 1. TCP allocates an skb using alloc_skb_fclone()\n   (from skbuff_fclone_cache) [1]\n2. The skb is cloned via skb_clone() using the pre-allocated fclone\n[3] 3. The cloned skb is queued to sk_error_queue for timestamp\nreporting 4. Userspace reads the error queue via recvmsg(MSG_ERRQUEUE)\n5. sock_recv_errqueue() calls put_cmsg() to copy serr-\u003eee from skb-\u003ecb\n[4] 6. __check_heap_object() fails because skbuff_fclone_cache has no\n   usercopy whitelist [5]\n\nWhen cloned skbs allocated from skbuff_fclone_cache are used in the\nsocket error queue, accessing the sock_exterr_skb structure in skb-\u003ecb\nvia put_cmsg() triggers a usercopy hardening violation:\n\n[    5.379589] usercopy: Kernel memory exposure attempt detected from SLUB object 'skbuff_fclone_cache' (offset 296, size 16)!\n[    5.382796] kernel BUG at mm/usercopy.c:102!\n[    5.383923] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI\n[    5.384903] CPU: 1 UID: 0 PID: 138 Comm: poc_put_cmsg Not tainted 6.12.57 #7\n[    5.384903] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n[    5.384903] RIP: 0010:usercopy_abort+0x6c/0x80\n[    5.384903] Code: 1a 86 51 48 c7 c2 40 15 1a 86 41 52 48 c7 c7 c0 15 1a 86 48 0f 45 d6 48 c7 c6 80 15 1a 86 48 89 c1 49 0f 45 f3 e8 84 27 88 ff \u003c0f\u003e 0b 490\n[    5.384903] RSP: 0018:ffffc900006f77a8 EFLAGS: 00010246\n[    5.384903] RAX: 000000000000006f RBX: ffff88800f0ad2a8 RCX: 1ffffffff0f72e74\n[    5.384903] RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff87b973a0\n[    5.384903] RBP: 0000000000000010 R08: 0000000000000000 R09: fffffbfff0f72e74\n[    5.384903] R10: 0000000000000003 R11: 79706f6372657375 R12: 0000000000000001\n[    5.384903] R13: ffff88800f0ad2b8 R14: ffffea00003c2b40 R15: ffffea00003c2b00\n[    5.384903] FS:  0000000011bc4380(0000) GS:ffff8880bf100000(0000) knlGS:0000000000000000\n[    5.384903] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[    5.384903] CR2: 000056aa3b8e5fe4 CR3: 000000000ea26004 CR4: 0000000000770ef0\n[    5.384903] PKRU: 55555554\n[    5.384903] Call Trace:\n[    5.384903]  \u003cTASK\u003e\n[    5.384903]  __check_heap_object+0x9a/0xd0\n[    5.384903]  __check_object_size+0x46c/0x690\n[    5.384903]  put_cmsg+0x129/0x5e0\n[    5.384903]  sock_recv_errqueue+0x22f/0x380\n[    5.384903]  tls_sw_recvmsg+0x7ed/0x1960\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? schedule+0x6d/0x270\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n[    5.384903]  ? mutex_unlock+0x81/0xd0\n[    5.384903]  ? __pfx_mutex_unlock+0x10/0x10\n[    5.384903]  ? __pfx_tls_sw_recvmsg+0x10/0x10\n[    5.384903]  ? _raw_spin_lock_irqsave+0x8f/0xf0\n[    5.384903]  ? _raw_read_unlock_irqrestore+0x20/0x40\n[    5.384903]  ? srso_alias_return_thunk+0x5/0xfbef5\n\nThe crash offset 296 corresponds to skb2-\u003ecb within skbuff_fclones:\n  - sizeof(struct sk_buff) = 232 - offsetof(struct sk_buff, cb) = 40 -\n  offset of skb2.cb in fclones = 232 + 40 = 272 - crash offset 296 =\n  272 + 24 (inside sock_exterr_skb.ee)\n\nThis patch uses a local stack variable as a bounce buffer to avoid the hardened usercopy check failure.\n\n[1] https://elixir.bootlin.com/linux/v6.12.62/source/net/ipv4/tcp.c#L885\n[2] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5104\n[3] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5566\n[4] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c#L5491\n[5] https://elixir.bootlin.com/linux/v6.12.62/source/mm/slub.c#L5719","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: sock: fix hardened usercopy panic in sock_recv_errqueue","id":"CVE-2026-22977","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":7,"next":{"headline":"wifi: avoid kernel-infoleak from struct iw_point","id":"CVE-2026-22978"},"packages":[],"prev":{"headline":"net/sched: sch_qfq: Fix NULL deref when deactivating inactive aggregate in qfq_reset","id":"CVE-2026-22976"},"products":["Linux"],"published":"2026-01-21","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":"2026-10-19","vendors":["Linux"]},"summary":"A missing usercopy whitelist in the Linux kernel causes a panic when reading socket error queues, leading to denial of service.","url":"https://insights.sbomify.com/CVE-2026-22977/"}