CVE-2013-4123

NONECVSS 0.0Weaponized
0.0
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 80%
CISA-KEV: Not listedEPSS: 80%CVSS: —Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

client_side_request.cc in Squid 3.2.x before 3.2.13 and 3.3.x before 3.3.8 allows remote attackers to cause a denial of service via a crafted port number in a HTTP Host header.

CVSS v3
—
EG Score
0.0(none)
EPSS
99.6%
KEV
Not listed

Published

September 16, 2013

Last Modified

April 29, 2026

References (12)

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 2× in last 7d / 14× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-04 06:27 UTCEPSS rescore
  2. 2026-07-01 15:02 UTCEPSS rescore
  3. 2026-06-27 03:05 UTCEPSS rescore
  4. 2026-06-25 13:46 UTCEPSS rescore
  5. 2026-06-23 21:30 UTCEPSS rescore
  6. 2026-06-21 01:57 UTCEPSS rescore
  7. 2026-06-21 01:56 UTCEPSS rescore
  8. 2026-06-16 17:49 UTCEPSS rescore
  9. 2026-06-16 17:49 UTCEPSS rescore
  10. 2026-06-15 17:44 UTCEPSS rescore
  11. 2026-06-14 23:14 UTCEPSS rescore
  12. 2026-06-12 23:08 UTCEPSS rescore
  13. 2026-06-11 13:56 UTCEPSS rescore
  14. 2026-06-10 13:18 UTCEPSS rescore
  15. 2026-06-05 22:44 UTCEPSS rescore
  16. 2026-06-05 22:44 UTCEPSS rescore
  17. 2026-06-05 06:08 UTCEPSS rescore
  18. 2026-06-05 06:08 UTCEPSS rescore
  19. 2026-06-02 20:10 UTCEPSS rescore
  20. 2026-06-02 20:10 UTCEPSS rescore
  21. 2026-06-01 13:49 UTCEPSS rescore
  22. 2026-06-01 13:49 UTCEPSS rescore
  23. 2026-05-31 22:28 UTCEPSS rescore
  24. 2026-05-31 22:28 UTCEPSS rescore
  25. 2026-05-31 00:14 UTCEPSS rescore
Show 17 more
  1. 2026-05-31 00:14 UTCEPSS rescore
  2. 2026-05-29 13:41 UTCEPSS rescore
  3. 2026-05-29 13:41 UTCEPSS rescore
  4. 2026-05-28 22:28 UTCEG score recompute
  5. 2026-05-28 22:28 UTCGHSA enrichment
  6. 2026-05-27 13:38 UTCEPSS rescore
  7. 2026-05-27 13:38 UTCEPSS rescore
  8. 2026-05-26 07:16 UTCEPSS rescore
  9. 2026-05-26 07:16 UTCEPSS rescore
  10. 2026-05-22 21:15 UTCEPSS rescore
  11. 2026-05-22 21:15 UTCEPSS rescore
  12. 2026-05-22 21:15 UTCEPSS rescore
  13. 2026-05-21 22:39 UTCEPSS rescore
  14. 2026-05-20 22:37 UTCEPSS rescore
  15. 2026-05-20 22:37 UTCEPSS rescore
  16. 2026-05-18 21:29 UTCEPSS rescore
  17. 2026-05-18 21:29 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-26886✓ verified
    First seen Jul 16, 2013

    Squid 3.3.5 - Denial of Service (PoC)

    Open source ↗

Related CVEs(same CWE)

Frequently asked(4)

What is CVE-2013-4123?
CVE-2013-4123 is a none vulnerability published on September 16, 2013. clientsiderequest.cc in Squid 3.2.x before 3.2.13 and 3.3.x before 3.3.8 allows remote attackers to cause a denial of service via a crafted port number in a HTTP Host header.
When was CVE-2013-4123 disclosed?
CVE-2013-4123 was first published in the National Vulnerability Database on September 16, 2013, with the most recent update on April 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2013-4123 actively exploited?
CVE-2013-4123 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
How do I remediate CVE-2013-4123?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2013-4123, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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