NFS: Fix use-after-free in nfs4_init_client()
Priority LOW 37CWE-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: 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: NFS: Fix use-after-free in nfs4_init_client() KASAN reports a use-after-free when attempting to mount two different exports through two different NICs that belong to the same server. Olga was able to hit this with kernels starting somewhere between 5.7 and 5.10, but I traced the patch that introduced the clear_bit() call to 4.13. So something must have changed in the refcounting of the clp pointer to make this call to nfs_put_client() the very last one.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00713 53rd percentileScored 2026-11-07
Fix Partial Linux (Linux): 4.14.237, 4.19.195, 5.4.126 +3Red Hat: 3 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.13 and later | 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13 | Patch available | CNA |
- Linux VendorLinux Affected 4.13 and later Fixed in 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.13 to before 4.14.237; 4.15 to before 4.19.195; 4.20 to before 5.4.126; 5.5 to before 5.10.44; 5.11 to before 5.12.11 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | 5.13 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | 5.13 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | 5.13 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | 5.13 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* | 5.13 rc5 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.13 to before 4.14.237; 4.15 to before 4.19.195; 4.20 to before 5.4.126; 5.5 to before 5.10.44; 5.11 to before 5.12.11 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* Versions 5.13 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* Versions 5.13 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* Versions 5.13 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* Versions 5.13 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* Versions 5.13 rc5 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
Not affected: 1 product
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-47259
- 2026-10-03 Alias added: GHSA-w7j7-m99g-gcgq
References
Patch 6
- https://git.kernel.org/stable/c/c7eab9e2d7b4e983ce280276fb920af649955897
- https://git.kernel.org/stable/c/42c10b0db064e45f5c5ae7019bbf2168ffab766c
- https://git.kernel.org/stable/c/3e3c7ebbfac152d08be75c92802a64a1f6471a15
- https://git.kernel.org/stable/c/c3b6cf64dfe4ef96e7341508d50d6998da7062c7
- https://git.kernel.org/stable/c/72651c6579a25317a90536181d311c663d0329ab
- https://git.kernel.org/stable/c/476bdb04c501fc64bf3b8464ffddefc8dbe01577
More Linux Kernel vulnerabilities
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- 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
Sources
- CVE-2021-47259 · CVE Program
- CVE-2021-47259 · NVD
- FIRST EPSS
- GHSA-w7j7-m99g-gcgq · GitHub Advisory Database · CC BY 4.0
- CVE-2021-47259 · Red Hat security data · CC BY 4.0
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