Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-3999

CVE-2021-3999HIGH

n/a glibc — A flaw was found in glibc.

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   L   L   L   N  U  H  H  H    7.8   .0081   56.1     —

AFFECTED
  Product  Versions                           Fixed
  glibc    Fixed in glibc v2.31 and above. –  —

TIMELINE
  Nov 22  Reserved by redhat
  Aug 24  Published (CNA: redhat)
  Oct 14  EXPLOIT PUBLISHED — CVE-2021-3999 (glibc). Public exploit reference added.

CWE-193 · CNA: redhat · CVSS v3.1 · 10 references · NVD status: Modified

Description

A flaw was found in glibc. An off-by-one buffer overflow and underflow in getcwd() may lead to memory corruption when the size of the buffer is exactly 1. A local attacker who can control the input buffer and size passed to getcwd() in a setuid program could use this flaw to potentially execute arbitrary code and escalate their privileges on the system.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
November 22, 2021	Reserved	Reserved by redhat
August 24, 2022	Published	Published (CNA: redhat)
October 14, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2021-3999 (glibc). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	glibc	—	Fixed in glibc v2.31 and above.	—

Weaknesses

CWE-193

References (10)

https://access.redhat.com/security/cve/CVE-2021-3999 [Third Party Advisory]
https://bugzilla.redhat.com/show_bug.cgi?id=2024637 [Issue Tracking, Third Party Advisory]
https://cert-portal.siemens.com/productcert/html/ssa-398330.html
https://cert-portal.siemens.com/productcert/html/ssa-831302.html
https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html [Mailing List, Third Party Advisory]
https://security-tracker.debian.org/tracker/CVE-2021-3999 [Third Party Advisory]
https://security.netapp.com/advisory/ntap-20221104-0001/ [Third Party Advisory]
https://sourceware.org/bugzilla/show_bug.cgi?id=28769 [Issue Tracking, Third Party Advisory]
https://sourceware.org/git/gitweb.cgi?p=glibc.git%3Bh=23e0e8f5f1fb5ed150253d986ecccdc90c2dcd5e
https://www.openwall.com/lists/oss-security/2022/01/24/4 [Exploit, Mailing List, Third Party Advisory]

Authoritative record: CVE-2021-3999 at cve.org

Weaknesses: CWE-193

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-3999 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.