CVE-2025-5777 | NetScaler ADC and NetScaler Gateway - Insufficient input validation leading to memory overread

Exp

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

Published: 2025-06-17 Last update: 2025-10-30 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-5777 is rated Critical Active Threat (91.7/100): CVSS Critical severity, with high exploitation likelihood (EPSS 64.97%, 98th percentile). CISA KEV confirms active exploitation (added 2025-07-10) affecting Citrix / NetScaler ADC and Gateway. a weakness (CWE-125) Unauthenticated remote administrative access may be possible. The CISA remediation deadline has passed—treat as an emergency patch priority.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

CISA KEV Record for CVE-2025-5777

Name: Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability · CISA KEV detail

Exploit added: 2025-07-10

Action due: 2025-07-11

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.

Public exploit references (Exploit-DB) for CVE-2025-5777

EDB-ID Source Kind Published Link
52401 exploit_db edb 2025-08-11 Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-5777

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-03 71.45% 64.97% -6.48%
2 2026-05-27 64.97% 71.45% +6.48%
3 2026-05-13 — 64.97% —

Full EPSS history (70 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-5777

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.3 4.0 CRITICAL
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/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 Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:L)
Limited confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:L)
Limited integrity impact on subsequent systems.
Subsequent system availability impact (SA:L)
Limited availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2025-5777

Affected software / configurations for CVE-2025-5777

Vendor Product Version Raw CPE
citrix netscaler_application_delivery_controller >= 12.1, < 12.1-55.328 cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
citrix netscaler_application_delivery_controller >= 13.1, < 13.1-37.235 cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:fips:*:*:*
citrix netscaler_application_delivery_controller >= 13.1, < 13.1-37.235 cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:ndcpp:*:*:*
citrix netscaler_application_delivery_controller >= 13.1, < 13.1-58.32 cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
citrix netscaler_application_delivery_controller >= 14.1, < 14.1-43.56 cpe:2.3:a:citrix:netscaler_application_delivery_controller:*:*:*:*:-:*:*:*
citrix netscaler_gateway >= 13.1, < 13.1-58.32 cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*
citrix netscaler_gateway >= 14.1, < 14.1-43.56 cpe:2.3:a:citrix:netscaler_gateway:*:*:*:*:*:*:*:*

References for CVE-2025-5777

URL Tags
https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420 Vendor Advisory
https://citrixbleed.com Broken Link Third Party Advisory
https://horizon3.ai/attack-research/attack-blogs/cve-2025-5777-citrixbleed-2-write-up-maybe/ Third Party Advisory
https://labs.watchtowr.com/how-much-more-must-we-bleed-citrix-netscaler-memory-disclosure-citrixbleed-2-cve-2025-5777/ Third Party Advisory
https://www.bleepingcomputer.com/news/security/cisa-tags-citrix-bleed-2-as-exploited-gives-agencies-a-day-to-patch/ Press/Media Coverage Third Party Advisory
https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/ Third Party Advisory
https://www.theregister.com/2025/07/10/cisa_citrixbleed_kev/ Press/Media Coverage
https://doublepulsar.com/citrixbleed-2-exploitation-started-mid-june-how-to-spot-it-f3106392aa71 Third Party Advisory
https://reliaquest.com/blog/threat-spotlight-citrix-bleed-2-vulnerability-in-netscaler-adc-gateway-devices/ Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-5777 US Government Resource
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