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CVE-2019-13608

Citrix StoreFront Server XML External Entity (XXE) Processing Vulnerability

Citrix StoreFront Server before 1903, 7.15 LTSR before CU4 (3.12.4000), and 7.6 LTSR before CU8 (3.0.8000) allows XXE attacks.

CheckOps priority index
6.9/10 Patch within 7 days
Severity7.5
Probability3.0
Exploitation5/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 30.0% higher than 98.2% of CVEs
CVSS 3.1 7.5 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:
Exploited for 1,826 days 03 Nov 2021
CISA due date 03 May 2022 for US federal agencies

Exploitation probability EPSS · FIRST

05010026 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 5 / 5

  • KEV catalog (CISA)03 Nov 2021
  • Exploited in EUVD (ENISA)03 Nov 2021
  • Used by ransomwareyes
  • EPSS above 10 %30.0%
  • No account, over the networkyes

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

StoreFront Server
Weaknesses (CWE)
CWE-611

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

  5. EPSS peak: 30.0%

References

Other exploited vulnerabilities from the same vendor

  • CVE-2026-88779Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
    6.2 · Actively exploited
  • CVE-2026-88772Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
    8.5 · Actively exploited
  • CVE-2026-88771Citrix NetScaler Improper Input Validation Vulnerability
    8.7 · Actively exploited
  • CVE-2026-19490Citrix NetScaler Authentication Bypass Using an Alternate Path or Channel Vulnerability
    7.1 · Actively exploited
  • CVE-2026-8452Citrix NetScaler ADC and NetScaler Gateway Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability
    5.4 · Actively exploited
  • CVE-2026-3055Citrix NetScaler Out-of-Bounds Read Vulnerability
    8.9 · Background exploitation

Are you affected?

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities