7.1

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

Modified
AliasesUBUNTU-CVE-2021-46952DEBIAN-CVE-2021-46952
Published 27-02-2024Last modified 11-05-2026

Vulnerability summary

CVE-2021-46952 is a high (CVSS 7.1) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 20.6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.1, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.1/10
010
High · v3.1 (NVD)
EPSS score
0.28%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 27-02-2024
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

21%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.28% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu62 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 9954bf92c0cddd50a2a470be302e1c1ffdf21d42, < 96fa26b74cdcf9f5c98996bf36bec9fb5b19ffe2 | ≥ 9954bf92c0cddd50a2a470be302e1c1ffdf21d42, < 2f3380121d49e829fb73ba86240c181bc32ad897 | ≥ 9954bf92c0cddd50a2a470be302e1c1ffdf21d42, < 3d0163821c035040a46d816a42c0780f0f0a30a8 | ≥ 9954bf92c0cddd50a2a470be302e1c1ffdf21d42, < c09f11ef35955785f92369e25819bf0629df2e59 | 5.6
  • linux_kernel≥ 5.6.0, < 5.10.36 | ≥ 5.11.0, < 5.11.20 | ≥ 5.12.0, < 5.12.3
Debian1 product
  • linux< 5.10.38-1

3 vendors · 65 products

References

8 links