CVE-2021-38166: debian debian_linux Integer Overflow or Wraparound
Vulnerability summary
CVE-2021-38166 is a high (CVSS 7.8) Integer Overflow or Wraparound vulnerability in debian debian_linux. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 24.7% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 13 · Related 10Timeline
- 07-08-2021PublishedVulnerability first disclosed.
- 08-10-2026Last modifiedVulnerability information updated.
Description
In kernel/bpf/hashtab.c in the Linux kernel through 5.13.8, there is an integer overflow and out-of-bounds write when many elements are placed in a single bucket. NOTE: exploitation might be impractical without the CAP_SYS_ADMIN capability.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.32%
Chance of exploitation in the next 30 days
Percentile
25%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.32% 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 cause- CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu31 products
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11< 5.11.0-1020.21~20.04.2
- linux-aws-5.3All versions (No fix recorded)
- linux-aws-5.8All versions (No fix recorded)
- linux-azureAll versions (No fix recorded)
Debian2 products
- linux< 5.14.6-1
- debian_linuxEOL11.0
Fedoraproject1 product
- fedoraEOL33 | 34
Linux1 product
- linux_kernel≥ 5.6, < 5.10.60 | ≥ 5.11, < 5.13.12
4 vendors · 35 products
