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CVE-2025-6543· NVD / CVE Program· CNA Citrix

Memory overflow vulnerability leading to unintended control flow and Denial of Service

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

CriticalCVSS 9.2 · v4.0KEVWeaponized Fix available
Published
Jun 25, 2025
Updated
Jun 17, 2026
EPSS
10.6% · 96th percentile
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Report tools

JSON

Action score

69

This week

Don’t wait for the next maintenance window.

CVSS
36 / 40 · 9.2 / 10
CISA KEV
30 / 30 · Listed
EPSS
3 / 30 · 10.6%

CISA SSVC decision

Exploitation
active
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Citrix
9.2
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Jun 30, 2025. That signals real attacks, not theory.

Remediation deadline for government agencies: Jul 21, 2025.

Affected systems

VendorProduct
citrixnetscaler application delivery controller
citrixnetscaler gateway

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • citrix netscaler gateway13.1 and later · before 13.1-59.19
  • citrix netscaler gateway14.1 and later · before 14.1-47.46

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Citrix). Independent of NVD's CPE analysis and usually ahead of it.

  • NetScaler ADC

    • 14.1 and later · before 47.46affected · patch
    • 13.1 and later · before 59.19affected · patch
    • 13.1 FIPS and NDcPP and later · before 37.236affected · patch

  • NetScaler Gateway

    • 14.1 and later · before 47.46affected · patch
    • 13.1 and later · before 59.19affected · patch
    • 13.1 FIPS and NDcPP and later · before 37.236affected · patch

Same product

citrix: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-3519Unauthenticated remote code executionKEV
    99Now
  • CVE-2025-5777NetScaler ADC and NetScaler Gateway - Insufficient input validation leading to memory overreadKEV
    97Now
  • CVE-2023-4966Unauthenticated sensitive information disclosureKEV
    90Now
  • CVE-2023-6549Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated DenialKEV
    77This week
  • CVE-2025-7775Memory overflow vulnerability leading to Remote Code Execution and/or Denial of ServiceKEV
    72This week
  • CVE-2026-19490NetScaler ADC and NetScaler Gateway Security Bulletin for CVE-2026-19490KEV
    69This week

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
NetScaler ADC37.236Vendor (CNA)
NetScaler ADC47.46Vendor (CNA)
NetScaler ADC59.19Vendor (CNA)
NetScaler Gateway37.236Vendor (CNA)
NetScaler Gateway47.46Vendor (CNA)
NetScaler Gateway59.19Vendor (CNA)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Proof-of-concept repository on GitHub ×3

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:52025-06-26
Proof-of-concept repository on GitHubstars:02025-06-30
Proof-of-concept repository on GitHubstars:62025-07-03

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+1 d
  3. CISA KEV+5 d
  4. TodaySep 30, 2026+462 d
EPSS, last 120 days+1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2023-6549525 days apartImproper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated DenialKEV
    77This week
  • CVE-2025-777562 days apartMemory overflow vulnerability leading to Remote Code Execution and/or Denial of ServiceKEV
    72This week
  • CVE-2026-88772459 days apartMemory overflow vulnerability leading to Remote Code Execution or Denial of ServiceKEV
    68This week
  • CVE-2026-8452370 days apartMemory overflow vulnerability leading to unpredictable or erroneous behavior and Denial of ServiceKEV
    65This week
  • CVE-2025-777662 days apartMemory overflow vulnerability leading to unpredictable or erroneous behavior and Denial of Service
    37Monitor
  • CVE-2026-8655370 days apartMultiple Memory overflow vulnerabilities leading to unpredictable or erroneous behavior and Denial of Service
    35Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records