Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability
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
What happened
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
CISA lists it as exploited, added 10 Jul 2025.
Does it affect you
Names Citrix NetScaler ADC. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Follow the vendor advisory for the fixed release and any interim mitigation.
support.citrix.com - Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
cisa.gov
CISA’s notes for this entry:
Affected, as published to NVD
- citrix-adc
- Citrix NetScaler ADC: 12.1 up to the fix in 12.1-55.328
The record
- NVD status
- Analyzed
- Published
- 17 Jun 2025, last modified 08 Oct 2026 (NVD)
- Severity
- CVSS 3.1 base score 7.5, High — computed here from the vector; NVD states 7.5.
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness
- CWE-125 Out-of-bounds Read, CWE-908 Use of Uninitialized Resource (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 10 Jul 2025; federal remediation due 11 Jul 2025. CISA records known use in ransomware campaigns. CISA entry
- Exploit probability
- EPSS 100.0%, 100th percentile — FIRST, scored 23 Oct 2026. FIRST EPSS
- Vendor
- Citrix · NetScaler ADC and Gateway (CISA)
References on the NVD record
- support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420Vendor Advisory
- citrixbleed.comBroken LinkThird Party Advisory
- horizon3.ai/attack-research/attack-blogs/cve-2025-5777-citrixbleed-2-write-up-maybe/Third Party Advisory
- labs.watchtowr.com/how-much-more-must-we-bleed-citrix-netscaler-memory-disclosure-citrixbleed-2-cve-2025-5777/Third Party Advisory
- bleepingcomputer.com/news/security/cisa-tags-citrix-bleed-2-as-exploited-gives-agencies-a-day-to-patch/Press/Media CoverageThird Party Advisory
- netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/Third Party Advisory
- doublepulsar.com/citrixbleed-2-exploitation-started-mid-june-how-to-spot-it-f3106392aa71Third Party Advisory
- reliaquest.com/blog/threat-spotlight-citrix-bleed-2-vulnerability-in-netscaler-adc-gateway-devices/Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-5777US Government Resource
- theregister.com/2025/07/10/cisa_citrixbleed_kev/Press/Media Coverage
Reporting that names this identifier
- Ransomware Groups Turn to Citrix Bleed 2, BYOVD, and Supply Chain Credentials — The Hacker News, 4 mo ago
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.