CVE & CISA-KEV Catalog

CVE-2021-3999

HIGH
7.8
CVSS v3
NVD

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.

CWE-193

How to fix

Remediation Available
glibcDebian
Fixed in:2.31-13+deb11u4CVE-2021-3999
Fixed in:2.33-4CVE-2021-3999
Fixed in:2.33-4CVE-2021-3999
Fixed in:2.33-4CVE-2021-3999
eglibcUbuntu
Fixed in:2.19-0ubuntu6.15+esm3USN-6762-1
glibcUbuntu
Fixed in:2.23-0ubuntu11.3+esm6USN-6762-1
Fixed in:2.23-0ubuntu11.3+esm1USN-5310-2
Fixed in:2.27-3ubuntu1.6+esm2USN-6762-1
Fixed in:2.27-3ubuntu1.5USN-5310-1
Fixed in:2.31-0ubuntu9.7USN-5310-1
libc6Ubuntu
Fixed in:2.19-0ubuntu6.15+esm3USN-6762-1
Fixed in:2.23-0ubuntu11.3+esm1USN-5310-2
Fixed in:2.23-0ubuntu11.3+esm6USN-6762-1
Fixed in:2.27-3ubuntu1.5USN-5310-1
Fixed in:2.27-3ubuntu1.6+esm2USN-6762-1
Fixed in:2.31-0ubuntu9.7USN-5310-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.72%probability of exploitation in 30 days
49thpercentile

Moderate risk: more likely to be exploited than 49% of all known CVEs.

References

Exploit1
Other references1
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-12-02.