NVD / CVE Program· CNA Linux

CVE-2026-53393: nfsd: reset write verifier on deferred writeback errors

Noroxi assessment

Priority: Monitor (action score 22/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.12% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
Fixed version: Linux Linux 1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e, 2090b05803faab8a9fa62fbff871007862cac1b7, 4367afc119c51e17a616f6908772b7e2c2c4013f; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e, 2090b05803faab8a9fa62fbff871007862cac1b7, 4367afc119c51e17a616f6908772b7e2c2c4013f; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.5 · v3.1—No exploit Fix available

Denial of service

openSUSE-SU-2026:11339-1

Published: Jul 19, 2026
Updated: Aug 17, 2026
EPSS: 0.1% · 2th percentile
CWE: —

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 22 / 40 · 5.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

linux linux kernel5.10.124 and later · before 5.10.261
linux linux kernel5.15.49 and later · before 5.15.212
linux linux kernel5.17 and later · before 6.1.178
linux linux kernel6.2 and later · before 6.6.145
linux linux kernel6.7 and later · before 6.12.95
linux linux kernel6.13 and later · before 6.18.38
linux linux kernel6.19 and later · before 7.1.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

Linux Linux
- 5.17affected
- f14816f2f928c560d28ba344af689f56efcd6f55 and later · before b8e5894e56cff70fa245628fe16f0ad6367f8090affected · git
- 3145fe0ebb16e1715ad541a301bc6675c8375fcd and later · before bc2baca02ec56da7707a74ed5d340b0a1dff1841affected · git
- 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb and later · before 43b65d2997963e80e8d8d86520bcb1e0751227deaffected · git
- 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb and later · before 666e837b247fcadf2d8d508b9b0e49d720393eb4affected · git
- 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb and later · before 1dd664b39774a9c89b72de8e59bf9ef4b3aaff2eaffected · git
- 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb and later · before 4367afc119c51e17a616f6908772b7e2c2c4013faffected · git
- 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb and later · before b027cca33c97354149fcc0ddeede4525c41093cdaffected · git
- 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb and later · before 2090b05803faab8a9fa62fbff871007862cac1b7affected · git
- 5.10.124 and later · before 5.10.261affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.180-1	6.1.180-1
Debian:13	linux	before 6.12.95-1	6.12.95-1
Debian:14	linux	before 7.1.3-1	7.1.3-1
openSUSE:Tumbleweed	kernel-source	before 7.1.4-1.1	7.1.4-1.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
90Now
CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
89Now
CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
85Now

Published before and after this one in the same product

← EarlierCVE-2026-53389Jul 19, 2026 · net/tcp-ao: fix use-after-free of key in del_async path
31Monitor
← EarlierCVE-2026-53390Jul 19, 2026 · ksmbd: fix out-of-bounds read in smb_check_perm_dacl()
32Monitor
Later →CVE-2026-53395Jul 19, 2026 · nfsd: fix dead ACL conflict guard in nfsd4_create
30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
Linux Linux	1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e	Vendor (CNA)
Linux Linux	2090b05803faab8a9fa62fbff871007862cac1b7	Vendor (CNA)
Linux Linux	4367afc119c51e17a616f6908772b7e2c2c4013f	Vendor (CNA)
Linux Linux	43b65d2997963e80e8d8d86520bcb1e0751227de	Vendor (CNA)
Linux Linux	5.10.261	Vendor (CNA)
Linux Linux	5.15.212	Vendor (CNA)
Linux Linux	666e837b247fcadf2d8d508b9b0e49d720393eb4	Vendor (CNA)
Linux Linux	b027cca33c97354149fcc0ddeede4525c41093cd	Vendor (CNA)
Linux Linux	b8e5894e56cff70fa245628fe16f0ad6367f8090	Vendor (CNA)
Linux Linux	bc2baca02ec56da7707a74ed5d340b0a1dff1841	Vendor (CNA)
azl3 kernel 6.6.144.1-1 on Azure Linux 3.0	6.6.145.2-1 · CBL-Mariner Releases	Microsoft (MSRC)
debian:linux	6.1.180-1 · Debian:12	Package registry (OSV)
opensuse:kernel-source	7.1.4-1.1 · openSUSE:Tumbleweed	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-26-0576 · Jul 20, 2026(Linux Kernel Güvenlik Bildirimi)

All national notices →

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:11 PM UTC

For records you follow, these changes also arrive as notifications. →

References

git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records