nfsd: reset write verifier on deferred writeback errors
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: reset write verifier on deferred writeback errors nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the server's write verifier (nn->writeverf) when this check fails. Every other durable-storage-failure path in these functions calls commit_reset_write_verifier() before returning an error. The missing rotation means clients holding UNSTABLE write data under the current verifier will COMMIT, receive the unchanged verifier back, and conclude their data is durable — silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 §3.3.7, RFC 8881 §18.32). Add commit_reset_write_verifier() calls at both filemap_check_wb_err() error sites, matching the pattern used by adjacent error paths in the same functions. The helper already filters -EAGAIN and -ESTALE internally, so the calls are unconditionally safe.
Why it matters now
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
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.10.124 to before 5.10.261; 5.15.49 to before 5.15.212 | 5.10.261, 5.15.212 | Patch available | CNA |
| Linux | Linux | 5.17 and later | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 5.10.124 to before 5.10.261; 5.15.49 to before 5.15.212 Fixed in 5.10.261, 5.15.212 Patch available CNA
- Linux VendorLinux Affected 5.17 and later Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3, 7.2 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.10.124 to before 5.10.261; 5.15.49 to before 5.15.212; 5.17 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.10.124 to before 5.10.261; 5.15.49 to before 5.15.212; 5.17 to before 6.1.178; 6.2 to before 6.6.145; 6.7 to before 6.12.95; 6.13 to before 6.18.38; 6.19 to before 7.1.3 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212
- Fix · CNA Linux (Linux) Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
Not affected: 2 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2026-53393
- 2026-10-03 Alias added: GHSA-wm3m-j54f-523v
- 2026-10-13 Affected versions changed · Red Hat
- 2026-11-06 CISA SSVC decision points changed
References
Patch 8
- https://git.kernel.org/stable/c/b8e5894e56cff70fa245628fe16f0ad6367f8090
- https://git.kernel.org/stable/c/bc2baca02ec56da7707a74ed5d340b0a1dff1841
- https://git.kernel.org/stable/c/43b65d2997963e80e8d8d86520bcb1e0751227de
- https://git.kernel.org/stable/c/666e837b247fcadf2d8d508b9b0e49d720393eb4
- https://git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e
- https://git.kernel.org/stable/c/4367afc119c51e17a616f6908772b7e2c2c4013f
- https://git.kernel.org/stable/c/b027cca33c97354149fcc0ddeede4525c41093cd
- https://git.kernel.org/stable/c/2090b05803faab8a9fa62fbff871007862cac1b7
More Linux Kernel vulnerabilities
- 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
Sources
- CVE-2026-53393 · CVE Program
- CVE-2026-53393 · NVD
- FIRST EPSS
- GHSA-wm3m-j54f-523v · GitHub Advisory Database · CC BY 4.0
- CVE-2026-53393 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences