THREATPORT/VULNERABILITY/CVE-2021-28651
HIGH SEVERITY

CVE-2021-28651

Squid vulnerability

CVSS
7.5
EPSS
7.4%
EPSS pct
94th
Exploited
No known
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.
Affected vendor
Squid Cache
Affected product
Squid
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness type (CWE)
  • CWE-401 — Missing Release of Memory (Memory Leak)
Published
2021-05-27

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring no privileges, no user interaction. Successful exploitation leads to high impact to availability.

Its EPSS score of 7.4% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 94% of all scored CVEs.

Check your external exposure to CVE-2021-28651

  • Confirm whether Squid Cache Squid is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2021-28651.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-28651

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2021-28651 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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