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CVE Record

CVE-2022-49970: bpf, cgroup: Fix kernel BUG in purge_effective_progs

In the Linux kernel, the following vulnerability has been resolved: bpf, cgroup: Fix kernel BUG in purge_effective_progs Syzkaller reported a triggered kernel BUG as follows: ------------[ cut here ]------------ kernel BUG at kernel/bpf/cgroup.c:925! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 194 Comm: detach Not tainted 5.19.0-14184-g69dac8e431af #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:__cgroup_bpf_detach+0x1f2/0x2a0 Code: 00 e8 92 60 30 00 84 c0 75 d8 4c 89 e0 31 f6 85 f6 74 19 42 f6 84 28 48 05 00 00 02 75 0e 48 8b 80 c0 00 00 00 48 85 c0 75 e5 <0f> 0b 48 8b 0c5 RSP: 0018:ffffc9000055bdb0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888100ec0800 RCX: ffffc900000f1000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff888100ec4578 RBP: 0000000000000000 R08: ffff888100ec0800 R09: 0000000000000040 R10: 0000000000000000 R11: 0000000000000000 R12: ffff888100ec4000 R13: 000000000000000d R14: ffffc90000199000 R15: ffff888100effb00 FS: 00007f68213d2b80(0000) GS:ffff88813bc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f74a0e5850 CR3: 0000000102836000 CR4: 00000000000006e0 Call Trace: <TASK> cgroup_bpf_prog_detach+0xcc/0x100 __sys_bpf+0x2273/0x2a00 __x64_sys_bpf+0x17/0x20 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f68214dbcb9 Code: 08 44 89 e0 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff8 RSP: 002b:00007ffeb487db68 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 000000000000000b RCX: 00007f68214dbcb9 RDX: 0000000000000090 RSI: 00007ffeb487db70 RDI: 0000000000000009 RBP: 0000000000000003 R08: 0000000000000012 R09: 0000000b00000003 R10: 00007ffeb487db70 R11: 0000000000000246 R12: 00007ffeb487dc20 R13: 0000000000000004 R14: 0000000000000001 R15: 000055f74a1011b0 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- Repetition steps: For the following cgroup tree, root | cg1 | cg2 1. attach prog2 to cg2, and then attach prog1 to cg1, both bpf progs attach type is NONE or OVERRIDE. 2. write 1 to /proc/thread-self/fail-nth for failslab. 3. detach prog1 for cg1, and then kernel BUG occur. Failslab injection will cause kmalloc fail and fall back to purge_effective_progs. The problem is that cg2 have attached another prog, so when go through cg2 layer, iteration will add pos to 1, and subsequent operations will be skipped by the following condition, and cg will meet NULL in the end. `if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI))` The NULL cg means no link or prog match, this is as expected, and it's not a bug. So here just skip the no match situation.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel flaw in cgroup BPF cleanup that can trigger a kernel BUG during program detach under allocation-failure conditions. The practical business concern is host instability or denial of service on affected kernels. The provided sources do not show remote exploitation or active exploitation.

Executive priority

Treat this as a reliability and local-denial-of-service kernel issue. Prioritize normal kernel patch cycles, with faster action for multi-tenant hosts or platforms where untrusted workloads may influence BPF or cgroup behavior.

Technical view

The bug is in cgroup BPF effective program purge logic. With nested cgroups and BPF programs attached using NONE or OVERRIDE mode, a kmalloc failure can cause detach cleanup to reach a NULL cgroup and hit a BUG condition. Stable kernel commits are referenced as fixes.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel code with cgroup BPF in use. Container hosts, observability stacks, and security tooling may use BPF, but the sources do not identify specific distributions, configurations, or privilege requirements.

Exploitation context

The source describes a syzkaller-triggered kernel BUG using nested cgroups, BPF attach/detach, and failslab fault injection. KEV is false, and the bundle provides no evidence of public exploitation, remote attack, or weaponized use.

Researcher notes

Evidence is limited to the CVE description and upstream stable references. The reproducer depends on fault injection and specific BPF/cgroup state. Required privileges, distribution impact, and exploitability beyond denial of service are not established in the provided sources.

Mitigation direction

  • Check vendor kernel advisories for CVE-2022-49970 applicability and fixed packages.
  • Prioritize updates for container hosts and systems using cgroup BPF.
  • Map running kernel versions against vendor backports, not only upstream version numbers.
  • If patching is delayed, restrict untrusted local access to BPF-capable operations.

Validation and detection

  • Inventory Linux kernel versions across production and container-host fleets.
  • Review vendor advisories for backported fixes matching the referenced stable commits.
  • Confirm whether cgroup BPF features are enabled or used operationally.
  • Monitor for unexpected kernel BUG, panic, or bpf/cgroup detach crash messages.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux3527e3cbb84d8868c4d4e91ba55915f96d39ec3d, 1f8ca9c40e6222ce431e9ba5dae3cccce8ef9443, be001f9da71eaa3b61e186fb88bde3279728bdca, 4c46091ee985ae84c60c5e95055d779fcd291d87, 6336388715afa419cc97d0255bda3bba1b96b7caunaffected
LinuxLinux5.10.138, 5.15.61, 5.19.2unaffected
Weakness

CWE details

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