CVE & CISA-KEV Catalog

CVE-2021-28651

HIGHEPSS 94th pctl
7.5
CVSS v3
NVD

Description

An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to a buffer-management bug, it allows a denial of service. When resolving a request with the urn: scheme, the parser leaks a small amount of memory. However, there is an unspecified attack methodology that can easily trigger a large amount of memory consumption.

CWE-401Missing Release of Memory (Memory Leak)

How to fix

Remediation Available
squidDebian
Fixed in:4.13-10CVE-2021-28651
Fixed in:4.13-10CVE-2021-28651
Fixed in:4.13-10CVE-2021-28651
Fixed in:4.13-10CVE-2021-28651
squidRocky
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squidRed Hat / RHEL
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squid-debuginfoRocky
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
squid-debuginfoRed Hat / RHEL
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squid-migration-scriptRocky
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squid-migration-scriptRed Hat / RHEL
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squid-sysvinitRed Hat / RHEL
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squid-sysvinitRocky
Fixed in:7:3.5.20-17.el7_9.14.ppc64RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
Fixed in:7:3.5.20-17.el7_9.14RHSA-2025:14414
squidUbuntu
Fixed in:3.5.12-1ubuntu7.16+esm3USN-6857-1
Fixed in:3.5.27-1ubuntu1.11USN-4981-1
Fixed in:3.5.27-1ubuntu1.14+esm2USN-6857-1
Fixed in:4.10-1ubuntu1.4USN-4981-1
squid3Ubuntu
Fixed in:3.5.12-1ubuntu7.16+esm3USN-6857-1
Fixed in:3.5.27-1ubuntu1.11USN-4981-1
Fixed in:3.5.27-1ubuntu1.14+esm2USN-6857-1

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 VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

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

Exploit Intelligence

7.45%probability of exploitation in 30 days
94thpercentile

High risk: more likely to be exploited than 94% of all known CVEs.

References

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Markdown

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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 2024-11-21.