CVE Vulnerabilities

CVE-2021-28651

Missing Release of Memory after Effective Lifetime

Published: May 27, 2021 | Modified: Sep 14, 2021
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P
RedHat/V2
RedHat/V3
7.4 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H
Ubuntu

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.

Weakness

The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

Affected Software

Name Vendor Start Version End Version
Squid Squid-cache 2.0 *
Squid Squid-cache 5.0 *
Red Hat Enterprise Linux 8 RedHat squid:4-8050020210618131503.b4937e53 *
Squid Ubuntu devel *
Squid Ubuntu focal *
Squid Ubuntu groovy *
Squid Ubuntu hirsute *
Squid Ubuntu impish *
Squid Ubuntu jammy *
Squid Ubuntu trusty *
Squid Ubuntu upstream *
Squid3 Ubuntu bionic *
Squid3 Ubuntu trusty *
Squid3 Ubuntu xenial *

Potential Mitigations

  • Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
  • For example, glibc in Linux provides protection against free of invalid pointers.
  • When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
  • To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References