THREATPORT/VULNERABILITY/CVE-2021-31807
MEDIUM SEVERITY

CVE-2021-31807

Squid vulnerability

CVSS
6.5
EPSS
16.0%
EPSS pct
97th
Exploited
No known
An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. An integer overflow problem allows a remote server to achieve Denial of Service when delivering responses to HTTP Range requests. The issue trigger is a header that can be expected to exist in HTTP traffic without any malicious intent.
Affected vendor
Squid Cache
Affected product
Squid
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness type (CWE)
  • CWE-190 — Integer Overflow or Wraparound
Published
2021-06-08

Risk analysis

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

Its EPSS score of 16.0% reflects a moderate probability of exploitation activity in the wild over the next 30 days, placing it above 97% of all scored CVEs.

Check your external exposure to CVE-2021-31807

  • Confirm whether Squid Cache Squid is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2021-31807.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-31807

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2021-31807 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

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