Skip to content
Fencer Vulns
critical 9.8

CVE-2021-45707 json

Out-of-bounds Write in nix

published 2021-09-27 5 y ago modified 2026-09-10 1 mo ago also GHSA-76w9-p8mg-j927 , GHSA-wgrg-5h56-jg27 , RUSTSEC-2021-0119 , EUVD-2022-0497

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

An issue was discovered in the nix crate 0.16.0 and later before 0.20.2, 0.21.x before 0.21.2, and 0.22.x before 0.22.2 for Rust. unistd::getgrouplist has an out-of-bounds write if a user is in more than 16 /etc/groups groups.

Patch / fix

  • crates.io nix 0.20.2, 0.21.2, 0.22.2, 0.23.0
  • nix_project nix 0.20.2, 0.21.2, 0.22.2
  • rust-nix Debian 14, Debian 13, Debian 12 0.23.0-1

debian advisories DEBIAN-CVE-2021-45707

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-45707 updated cvss 8.6

rust-nix: unistd:: getgrouplist has an out-of-bounds write

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.69% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 6.7 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
crates.io nix
>=0.16.0, <0.20.2
>=0.21.0, <0.21.2
>=0.22.0, <0.22.2
>=0.21.0-0, <0.21.2
>=0.22.0-0, <0.22.2
>=0.23.0-0, <0.23.0
0.20.2
0.21.2
0.22.2
0.23.0

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.