VULNpocalypse

CVE-2025-5777: Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

Description quoted from the CVE record (assigned by Citrix, published 2025-06-17).

Weakness: CWE-125 Out-of-bounds Read

How it can be exploited

Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since
2025-07-10
US federal deadline
2025-07-11
Ransomware use
Yes

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-07142, CNNVD-202506-1996, EDB-52401, EUVD-2025-18497, GHSA-29vj-j5w5-pcph

VEDAS cluster: VEDAS:BELLATRIXVEGA

Exploit Observer links 40 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (40)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (5)

Vulnerability databases and vendor advisories (6)

Catalogue entries, not exploit evidence.

136 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
1.000
very likely to be attacked soon
VEDAS
0.989
strong exploit evidence
On CISA KEV
Yes, since 2025-07-10
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.1Added to CISA KEV 2025-07-10CVE-2025-5777 EPSS over time2025-062026-11-01
VEDAS (exploit evidence)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.9Added to CISA KEV 2025-07-10CVE-2025-5777 VEDAS over time2025-062026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

Who is affected

ProductAffectedNot affected
NetScaler ADCfrom 14.1 before 43.56
from 13.1 before 58.32		Not stated
NetScaler Gatewayfrom 14.1 before 43.56
from 13.1 before 58.32		Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: citrix netscaler_application_delivery_controller, citrix netscaler_gateway, citrix_systems_inc. netscaler_application_delivery_controller, citrix_systems_inc. netscaler_gateway.

How to fix it

Fixed versions stated in the CVE record: 43.56, 58.32.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor guidance:

How to detect it

Nuclei template (active check)

Citrix NetScaler - Information Disclosure

Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

Name and description quoted from the template, written by VEDAS.

The template sends 1 request (POST /p/u/doAuthentication.do); it decides using dsl, regex matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2025-5777.yaml
Show the template (56 lines)
yaml
id: CVE-2025-5777

info:
  name: "Citrix NetScaler - Information Disclosure"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    Insufficient input validation leading to memory overread when the NetScaler is configured as a Gateway (VPN
    virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server
  reference:
    - https://www.exploit.observer/?keyword=CVE-2025-5777&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=netscaler&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2025-5777
    cwe-id: CWE-457
  metadata:
    verified: false
  tags: cve,cve2025,netscaler,citrix,exposure,kev,vkev,vuln
http:
  - raw:
      - |+
        POST /p/u/doAuthentication.do HTTP/1.0
        Host: {{Hostname}}
        bleed_attack: {{iteration}}
        Content-Type: application/x-www-form-urlencoded; charset=UTF-8
        Content-Length: 5

        login

    unsafe: true
    payloads:
      iteration:
        - "{{rand_int(1,5)}}"

    extractors:
      - type: regex
        name: iv
        part: body
        group: 1
        regex:
          - '<InitialValue>([^<]{10,})</InitialValue>'
        internal: true

    stop-at-first-match: true
    matchers:
      - type: dsl
        dsl:
          - 'len(iv) > 0'
          - 'contains(to_lower(header), "application/vnd.citrix.authenticateresponse")'
          - '!contains(body, "<InitialValue></InitialValue>")'
          - '!contains(to_string(iv), "false")'
          - '!contains(to_string(iv), "true")'
          - '!regex("^[A-Za-z0-9+/=\\s]+$", iv)'
        condition: and

CVE-2025-5777.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2025-5777 Citrix NetScaler - Information Disclosure. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2025-5777 Citrix NetScaler - Information Disclosure"; flow:established,to_server; http.uri; content:"/p/u/doAuthentication.do"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2025-5777; reference:url,https://www.exploit.observer/?keyword=CVE-2025-5777&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=netscaler&match=exact; sid:1008995; rev:1;)

CVE-2025-5777.rules on GitHub

Advisories on this CVE

References

Exploits and technical analysis

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.