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TI-2021-21840 Aliases CVE-2021-47179GHSA-w5g2-4rxc-h7x8

NFSv4: Fix a NULL pointer dereference in pnfs_mark_matching_lsegs_return()

Priority LOW 34CWE-476Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-476.

Summary

In the Linux kernel, the following vulnerability has been resolved: NFSv4: Fix a NULL pointer dereference in pnfs_mark_matching_lsegs_return() Commit de144ff4234f changes _pnfs_return_layout() to call pnfs_mark_matching_lsegs_return() passing NULL as the struct pnfs_layout_range argument. Unfortunately, pnfs_mark_matching_lsegs_return() doesn't check if we have a value here before dereferencing it, causing an oops. I'm able to hit this crash consistently when running connectathon basic tests on NFS v4.1/v4.2 against Ontap.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00676 52nd percentileScored 2026-11-07
Fix Fixed Linux (Linux): 5.12, 4.9.271, 4.14.235 +4

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
LinuxLinux5.11.20 to before 5.125.12Patch availableCNA
LinuxLinux4.9.269 to before 4.9.271; 4.14.233 to before 4.14.235; 4.19.191 to before 4.19.193; 5.4.118 to before 5.4.124; 5.10.36 to before 5.10.42; 5.12.3 to before 5.12.94.9.271, 4.14.235, 4.19.193, 5.4.124, 5.10.42, 5.12.9Patch availableCNA
  • Linux VendorLinux Affected 5.11.20 to before 5.12 Fixed in 5.12 Patch available CNA
  • Linux VendorLinux Affected 4.9.269 to before 4.9.271; 4.14.233 to before 4.14.235; 4.19.191 to before 4.19.193; 5.4.118 to before 5.4.124; 5.10.36 to before 5.10.42; 5.12.3 to before 5.12.9 Fixed in 4.9.271, 4.14.235, 4.19.193, 5.4.124, 5.10.42, 5.12.9 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*4.9.269 to before 4.9.271; 4.14.233 to before 4.14.235; 4.19.191 to before 4.19.193; 5.4.118 to before 5.4.124; 5.10.36 to before 5.10.42; 5.12.3 to before 5.12.9VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.9.269 to before 4.9.271; 4.14.233 to before 4.14.235; 4.19.191 to before 4.19.193; 5.4.118 to before 5.4.124; 5.10.36 to before 5.10.42; 5.12.3 to before 5.12.9 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.12
  • Fix · CNA Linux (Linux) Fixed in 4.9.271, 4.14.235, 4.19.193, 5.4.124, 5.10.42, 5.12.9

Vendor assessments

Red Hat

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

Not affected: 4 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-47179
  2. 2026-10-03 Alias added: GHSA-w5g2-4rxc-h7x8

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