NVD / CVE Program· CNA Linux

CVE-2021-46952: NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds

HighCVSS 7.1 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 28/100)

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: 0.28% (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 2f3380121d49e829fb73ba86240c181bc32ad897, 3d0163821c035040a46d816a42c0780f0f0a30a8, 96fa26b74cdcf9f5c98996bf36bec9fb5b19ffe2.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2f3380121d49e829fb73ba86240c181bc32ad897, 3d0163821c035040a46d816a42c0780f0f0a30a8, 96fa26b74cdcf9f5c98996bf36bec9fb5b19ffe2 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: NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds Fix shift out-of-bounds in xprt_calc_majortimeo(). This is caused by a garbage timeout (retrans) mount option being passed to nfs mount, in this case from syzkaller. If the protocol is XPRT_TRANSPORT_UDP, then 'retrans' is a shift value for a 64-bit long integer, so 'retrans' cannot be >= 64. If it is >= 64, fail the mount and return an error.

Memory safety

BDU:2024-03693

Published: Feb 27, 2024
Updated: Jun 17, 2026
EPSS: 0.2% · 20th percentile
CWE: CWE-125

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 28 / 40 · 7.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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

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
- 5.6affected
- 9954bf92c0cddd50a2a470be302e1c1ffdf21d42 and later · before 96fa26b74cdcf9f5c98996bf36bec9fb5b19ffe2affected · git
- 9954bf92c0cddd50a2a470be302e1c1ffdf21d42 and later · before 2f3380121d49e829fb73ba86240c181bc32ad897affected · git
- 9954bf92c0cddd50a2a470be302e1c1ffdf21d42 and later · before 3d0163821c035040a46d816a42c0780f0f0a30a8affected · git
- 9954bf92c0cddd50a2a470be302e1c1ffdf21d42 and later · before c09f11ef35955785f92369e25819bf0629df2e59affected · git
- before 5.6not affected · semver
- 5.10.36 and later · up to and including 5.10.*not affected · semver
- 5.11.20 and later · up to and including 5.11.*not affected · semver
- 5.12.3 and later · up to and including 5.12.*not affected · semver
- 5.13 and laternot affected · original_commit_for_fix

Affected versions

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

linux linux kernel5.6.0 and later · before 5.10.36
linux linux kernel5.11.0 and later · before 5.11.20
linux linux kernel5.12.0 and later · before 5.12.3

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 5.10.38-1	5.10.38-1

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-2021-46950Feb 27, 2024 · md/raid1: properly indicate failure when ending a failed write request
31Monitor
← EarlierCVE-2021-46951Feb 27, 2024 · tpm: efi: Use local variable for calculating final log size
22Monitor
Later →CVE-2021-46953Feb 27, 2024 · ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure
26Monitor

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	2f3380121d49e829fb73ba86240c181bc32ad897	Vendor (CNA)
Linux Linux	3d0163821c035040a46d816a42c0780f0f0a30a8	Vendor (CNA)
Linux Linux	96fa26b74cdcf9f5c98996bf36bec9fb5b19ffe2	Vendor (CNA)
Linux Linux	c09f11ef35955785f92369e25819bf0629df2e59	Vendor (CNA)
debian:linux	5.10.38-1 · Debian:12	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.