CVE-2021-45707

Memory corruption via stale group-buffer length

Published Dec 26, 2021 · Updated Aug 4, 2024

Out-of-bounds write in Rust nix crate 0.16.0 through 0.20.1, 0.21.0 through 0.21.1, and 0.22.0 through 0.22.1 allows local users to corrupt memory. The getgrouplist wrapper doubles its eight-entry buffer after libc reports it too small but retains libc's larger ngroups value, causing the next call to pass a length greater than the 16-entry allocation. Exploitation requires control of /etc/groups, which is normally restricted to root, and corrupts only the memory of a process that invokes the affected function.

CVSS severity9.8
Critical
EPSS probability1.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds write in Rust nix crate 0.16.0 through 0.20.1, 0.21.0 through 0.21.1, and 0.22.0 through 0.22.1 allows local users to corrupt memory. The getgrouplist wrapper doubles its eight-entry buffer after libc reports it too small but retains libc's larger ngroups value, causing the next call to pass a length greater than the 16-entry allocation. Exploitation requires control of /etc/groups, which is normally restricted to root, and corrupts only the memory of a process that invokes the affected function.

The record

CVE
CVE-2021-45707
Published
Dec 26, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NISTAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo