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Vulnerability record · public intelligence
CVE-2021-28662
UNKNOWN

CVE-2021-28662

Published May 27, 2021 · Updated Nov 3, 2026

Severity · CVSSUNKNOWN · Not scored
Known exploitationNot listed
EPSS / likelihood71.76%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
LOW
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. Security advisory ↗
  2. Patch commit ↗
  3. www.squid-cache.org ↗
  4. DSA-4924 ↗
  5. FEDORA-2021-c0bec55ec7 ↗
  6. FEDORA-2021-24af72ff2c ↗
  7. [oss-security] 20231011 Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days. ↗
  8. 20231016 Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days. ↗

Record history

Published May 27, 2021 · Last refreshed Nov 3, 2026

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