Read the docs
TI-2024-27321 Aliases CVE-2024-40958GHSA-8rq2-2hq7-cqr5

netns: Make get_net_ns() handle zero refcount net

Priority LOW 34CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 11 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

In the Linux kernel, the following vulnerability has been resolved: netns: Make get_net_ns() handle zero refcount net Syzkaller hit a warning: refcount_t: addition on 0; use-after-free. WARNING: CPU: 3 PID: 7890 at lib/refcount.c:25 refcount_warn_saturate+0xdf/0x1d0 Modules linked in: CPU: 3 PID: 7890 Comm: tun Not tainted 6.10.0-rc3-00100-gcaa4f9578aba-dirty #310 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:refcount_warn_saturate+0xdf/0x1d0 Code: 41 49 04 31 ff 89 de e8 9f 1e cd fe 84 db 75 9c e8 76 26 cd fe c6 05 b6 41 49 04 01 90 48 c7 c7 b8 8e 25 86 e8 d2 05 b5 fe 90 <0f> 0b 90 90 e9 79 ff ff ff e8 53 26 cd fe 0f b6 1 RSP: 0018:ffff8881067b7da0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff811c72ac RDX: ffff8881026a2140 RSI: ffffffff811c72b5 RDI: 0000000000000001 RBP: ffff8881067b7db0 R08: 0000000000000000 R09: 205b5d3730353139 R10: 0000000000000000 R11: 205d303938375420 R12: ffff8881086500c4 R13: ffff8881086500c4 R14: ffff8881086500b0 R15: ffff888108650040 FS: 00007f5b2961a4c0(0000) GS:ffff88823bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d7ed36fd18 CR3: 00000001482f6000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ? show_regs+0xa3/0xc0 ? __warn+0xa5/0x1c0 ? refcount_warn_saturate+0xdf/0x1d0 ? report_bug+0x1fc/0x2d0 ? refcount_warn_saturate+0xdf/0x1d0 ? handle_bug+0xa1/0x110 ? exc_invalid_op+0x3c/0xb0 ? asm_exc_invalid_op+0x1f/0x30 ? __warn_printk+0xcc/0x140 ? __warn_printk+0xd5/0x140 ? refcount_warn_saturate+0xdf/0x1d0 get_net_ns+0xa4/0xc0 ? __pfx_get_net_ns+0x10/0x10 open_related_ns+0x5a/0x130 __tun_chr_ioctl+0x1616/0x2370 ? __sanitizer_cov_trace_switch+0x58/0xa0 ? __sanitizer_cov_trace_const_cmp2+0x1c/0x30 ? __pfx_tun_chr_ioctl+0x10/0x10 tun_chr_ioctl+0x2f/0x40 __x64_sys_ioctl+0x11b/0x160 x64_sys_call+0x1211/0x20d0 do_syscall_64+0x9e/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5b28f165d7 Code: b3 66 90 48 8b 05 b1 48 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 8 RSP: 002b:00007ffc2b59c5e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5b28f165d7 RDX: 0000000000000000 RSI: 00000000000054e3 RDI: 0000000000000003 RBP: 00007ffc2b59c650 R08: 00007f5b291ed8c0 R09: 00007f5b2961a4c0 R10: 0000000029690010 R11: 0000000000000246 R12: 0000000000400730 R13: 00007ffc2b59cf40 R14: 0000000000000000 R15: 0000000000000000 </TASK> Kernel panic - not syncing: kernel: panic_on_warn set ... This is trigger as below: ns0 ns1 tun_set_iff() //dev is tun0 tun->dev = dev //ip link set tun0 netns ns1 put_net() //ref is 0 __tun_chr_ioctl() //TUNGETDEVNETNS net = dev_net(tun->dev); open_related_ns(&net->ns, get_net_ns); //ns1 get_net_ns() get_net() //addition on 0 Use maybe_get_net() in get_net_ns in case net's ref is zero to fix this

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00267 18th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.4.279, 5.10.221, 5.15.162 +4Red Hat: 3 advisoriesRed Hat: 11 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.2 and later5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10Patch availableCNA
  • Linux VendorLinux Affected 5.2 and later Fixed in 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.2 to before 5.4.279; 5.5 to before 5.10.221; 5.11 to before 5.15.162; 5.16 to before 6.1.96; 6.2 to before 6.6.36; 6.7 to before 6.9.7VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.10:rc1:*:*:*:*:*:*6.10 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.10:rc2:*:*:*:*:*:*6.10 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.10:rc3:*:*:*:*:*:*6.10 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:6.10:rc4:*:*:*:*:*:*6.10 rc4VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.2 to before 5.4.279; 5.5 to before 5.10.221; 5.11 to before 5.15.162; 5.16 to before 6.1.96; 6.2 to before 6.6.36; 6.7 to before 6.9.7 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.10:rc1:*:*:*:*:*:* Versions 6.10 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.10:rc2:*:*:*:*:*:* Versions 6.10 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.10:rc3:*:*:*:*:*:* Versions 6.10 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:6.10:rc4:*:*:*:*:*:* Versions 6.10 rc4 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10

Red Hat 3 advisories

  • RHSA-2024:7000 Released 2024-09-24 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux BaseOS (v. 8) bpftool-4.18.0-553.22.1.el8_10, kernel-4.18.0-553.22.1.el8_10, kernel-abi-stablelists-4.18.0-553.22.1.el8_10 +19
    • Red Hat Enterprise Linux CRB (v. 8) kernel-tools-libs-devel-4.18.0-553.22.1.el8_10
  • RHSA-2024:7001 Released 2024-09-24 · Red Hat rating Important
    kernel-rt security update
    • Red Hat Enterprise Linux NFV (v. 8) kernel-rt-4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core-4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-4.18.0-553.22.1.rt7.363.el8_10 +9
    • Red Hat Enterprise Linux RT (v. 8) kernel-rt-4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core-4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-4.18.0-553.22.1.rt7.363.el8_10 +7
  • RHSA-2024:5363 Released 2024-08-15 · Red Hat rating Important
    kernel security update
    • Red Hat Enterprise Linux AppStream (v. 9) kernel-64k-debug-devel-5.14.0-427.31.1.el9_4, kernel-64k-debug-devel-matched-5.14.0-427.31.1.el9_4, kernel-64k-devel-5.14.0-427.31.1.el9_4 +11
    • Red Hat Enterprise Linux BaseOS (v. 9) bpftool-7.3.0-427.31.1.el9_4, kernel-5.14.0-427.31.1.el9_4, kernel-64k-5.14.0-427.31.1.el9_4 +29
    • Red Hat Enterprise Linux CRB (v. 9) kernel-tools-libs-devel-5.14.0-427.31.1.el9_4, libperf-5.14.0-427.31.1.el9_4
    • Red Hat Enterprise Linux NFV (v. 9) kernel-rt-5.14.0-427.31.1.el9_4, kernel-rt-core-5.14.0-427.31.1.el9_4, kernel-rt-debug-5.14.0-427.31.1.el9_4 +11
    • Red Hat Enterprise Linux RT (v. 9) kernel-rt-5.14.0-427.31.1.el9_4, kernel-rt-core-5.14.0-427.31.1.el9_4, kernel-rt-debug-5.14.0-427.31.1.el9_4 +9

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 9AffectedNo fix planned: Will not fix
RHOAI-2.13-RHEL-8Fixed—
RHOAI-2.14-RHEL-8Fixed—
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2024:5363
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2024:7000
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2024:5363
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2024:7000
Red Hat Enterprise Linux CRB (v. 9)Fixed RHSA-2024:5363
Red Hat Enterprise Linux NFV (v. 8)Fixed RHSA-2024:7001
Red Hat Enterprise Linux NFV (v. 9)Fixed RHSA-2024:5363
Red Hat Enterprise Linux RT (v. 8)Fixed RHSA-2024:7001
Red Hat Enterprise Linux RT (v. 9)Fixed RHSA-2024:5363
Not affected: 2 products
  • Red Hat Enterprise Linux AppStream (v. 9)
  • Red Hat Enterprise Linux CRB (v. 9)

Timeline

  1. 2026-10-02 Threatist record created from CVE-2024-40958
  2. 2026-10-03 Alias added: GHSA-8rq2-2hq7-cqr5
  3. 2026-10-29 Affected versions changed · Red Hat
  4. 2026-10-30 Fix available: RHOAI-2.13-RHEL-8, RHOAI-2.14-RHEL-8 · Red Hat

References

Patch 7

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences