CVEs / CVE-2025-5777
CVE-2025-5777: Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability
- Known exploited in the CISA KEV catalog since 10 Jul 2025
- high 7.5 CVSS 3.1 (NVD)
- EPSS 99.9% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2025-5777
Summary
Citrix NetScaler ADC and Gateway contain an out-of-bounds read vulnerability due to insufficient input validation. This vulnerability can lead to memory overread when the NetScaler is configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server.
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
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| NetScaler ADC | from 14.1, before 43.56 | 43.56 |
| NetScaler ADC | from 13.1, before 58.32 | 58.32 |
| NetScaler Gateway | from 14.1, before 43.56 | 43.56 |
| NetScaler Gateway | from 13.1, before 58.32 | 58.32 |
Exploitation
| In CISA KEV since | 10 Jul 2025 |
|---|---|
| Due date for US federal agencies | 11 Jul 2025 |
| Used in ransomware campaigns | Known |
| 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. |
Severity
| CVSS 3.1 | 7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NScored by NVD |
|---|---|
| Weakness | CWE-125, CWE-908 |
References
- CVE-2025-5777 on NVD
- CVE-2025-5777 in the CISA KEV catalog
- https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420 (cited by CISA)
- 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
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.