CVE-2021-4090: linux kernel Out-of-bounds Write
Vulnerability summary
CVE-2021-4090 is a high (CVSS 7.1) Out-of-bounds Write vulnerability in linux kernel. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 27.3% of scored vulnerabilities.
Not severe (CVSS 7.1, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 3Timeline
- 18-02-2022PublishedVulnerability first disclosed.
- 14-10-2026Last modifiedVulnerability information updated.
Description
An out-of-bounds (OOB) memory write flaw was found in the NFSD in the Linux kernel. Missing sanity may lead to a write beyond bmval[bmlen-1] in nfsd4_decode_bitmap4 in fs/nfsd/nfs4xdr.c. In this flaw, a local attacker with user privilege may gain access to out-of-bounds memory, leading to a system integrity and confidentiality threat.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- OSV · DebianEcosystem advisory · calculated7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.34%
Chance of exploitation in the next 30 days
Percentile
27%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.34% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu36 products
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11< 5.11.0-1028.31~20.04.1
- linux-aws-5.13< 5.13.0-1012.13~20.04.1
- linux-aws-5.3All versions (No fix recorded)
- linux-aws-5.8All versions (No fix recorded)
Linux2 products
- kernel≥ 5.11, < 5.15.5
- linux_kernelEOL< 5.16 | 5.16 | 5.16:rc1
Debian1 product
- linux< 5.15.5-1
4 vendors · 47 products
References
14 links- security.netapp.com/advisory/ntap-20220318-0010/Third Party Advisory
