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NVD / CVE Program· CNA Citrix

CVE-2023-4966: Unauthenticated sensitive information disclosure

Noroxi assessment

Priority: Now (action score 90/100)

  • CISA has confirmed exploitation in the wild (Oct 18, 2023); it is known to be used in ransomware campaigns. Remediation deadline for US federal agencies: Nov 8, 2023.
  • A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
  • Probability of exploitation in the next 30 days: 99.9% (FIRST EPSS); higher than 99.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Citrix NetScaler ADC 37.164, 49.15, 55.300; Citrix NetScaler Gateway 49.15, 8.50, 92.19.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Patch today or shut off access. Upgrade to Citrix NetScaler ADC 37.164, 49.15, 55.300; Citrix NetScaler Gateway 49.15, 8.50, 92.19 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA  virtual server.

HighCVSS 7.5 · v3.1KEVWeaponized Fix available
Published
Oct 10, 2023
Updated
Jul 31, 2026
EPSS
99.9% · 99th percentile

Report tools

JSON

Action score

90

Now

Patch today or shut off access.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
30 / 30 · Listed
EPSS
30 / 30 · 99.9%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.5
CNA · Citrix
9.4
1.9 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A: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 Oct 18, 2023. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Nov 8, 2023.

Known to be used in ransomware campaigns.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-4966

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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 gateway13.0 and later · before 13.0-92.19
  • citrix netscaler gateway13.1 and later · before 13.1-49.15
  • citrix netscaler gateway14.1 and later · before 14.1-8.50

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.

  • Citrix NetScaler ADC

    • 14.1 and later · before 8.50affected · patch
    • 13.1 and later · before 49.15affected · patch
    • 13.0 and later · before 92.19affected · patch
    • 13.1-FIPS and later · before 37.164affected · patch
    • 12.1-FIPS and later · before 55.300affected · patch
    • 12.1-NDcPP and later · before 55.300affected · patch

  • Citrix NetScaler Gateway

    • 14.1 and later · before 8.50affected · patch
    • 13.1 and later · before 49.15affected · patch
    • 13.0 and later · before 92.19affected · 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-2026-3055Insufficient input validation leading to memory overreadKEV
    94Now

Published before and after this one in the same product

  • ← EarlierCVE-2023-3466Jul 19, 2023 · Reflected Cross-Site Scripting (XSS)
    25Monitor
  • ← EarlierCVE-2023-3467Jul 19, 2023 · Privilege Escalation to root administrator (nsroot)
    32Monitor
  • Later →CVE-2023-4967Oct 27, 2023 · Denial of Service in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AA
    30Monitor

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
Citrix NetScaler ADC37.164Vendor (CNA)
Citrix NetScaler ADC49.15Vendor (CNA)
Citrix NetScaler ADC55.300Vendor (CNA)
Citrix NetScaler ADC8.50Vendor (CNA)
Citrix NetScaler ADC92.19Vendor (CNA)
Citrix NetScaler Gateway49.15Vendor (CNA)
Citrix NetScaler Gateway8.50Vendor (CNA)
Citrix NetScaler Gateway92.19Vendor (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

  • Metasploit module ×1
  • Nuclei detection template ×2
  • Proof-of-concept repository on GitHub ×14

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
Metasploit moduleauxiliary/scanner/http/citrix_bleed_cve_2023_4966Citrix ADC (NetScaler) Bleed Scannerauxiliary2023-10-25
Nuclei detection templateNuclei template CVE-2023-4966 —
Nuclei detection templateNuclei template CVE-2023-6549 —
Proof-of-concept repository on GitHubstars:782023-10-24
Proof-of-concept repository on GitHubstars:102023-10-25
Proof-of-concept repository on GitHubstars:82023-10-25
Proof-of-concept repository on GitHubstars:12023-10-25
Proof-of-concept repository on GitHubstars:02023-10-27
Proof-of-concept repository on GitHubstars:52023-10-28
Proof-of-concept repository on GitHubstars:102023-10-29
Proof-of-concept repository on GitHubstars:02023-11-20
Proof-of-concept repository on GitHubstars:02023-11-27

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. CISA KEV+8 d
  3. First PoC+14 d
  4. Metasploit+15 d
  5. TodayOct 30, 2026+1116 d

No history yet (it accumulates with the daily EPSS job).

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.

No nightly-computed relations.

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.

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

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

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

nvd-primary

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

—

Change log

  1. Fix✗ → ✓

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

References

Show all references (2 more)

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

All records