---
title: "CVE-2025-5777: Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability"
url: https://erroneo.us/security/cve/CVE-2025-5777/
description: "CVE-2025-5777 (Citrix NetScaler ADC and Gateway): Exploited in the wild (CISA KEV). Insufficient input validation leading to memory overread when the…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-06-17
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-5777"
kev: true
cvss: 9.3
epss: 0.99972
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Citrix NetScaler ADC and Gateway. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-07-10, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-07-11 ; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns .
- EPSS 100.0% , percentile 100.0: FIRST’s model estimates a 100.0% chance of exploitation activity in the next 30 days, higher than 100.0% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Check exposure. Citrix Bleed 2: NetScaler Gateway Memory Leak — A pre-auth memory leak on internet-facing VPN gateways that was exploited within weeks; patched since June 2025, so the job now is proving you patched, killed sessions and were not session-hijacked.

## 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

## Affected products (CVE record)

- NetScaler ADC: 14.1 < 43.56, 13.1 < 58.32
- NetScaler Gateway: 14.1 < 43.56, 13.1 < 58.32

## Severity

- Citrix CVSS 4.0: 9.3 `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`

## Exploitation

- CISA KEV: added 2025-07-10; federal due date 2025-07-11. Known ransomware use: Known.
- 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.
- CISA SSVC assessment: exploitation active , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 99.97% probability of exploitation activity in the next 30 days; percentile 100.0.

## Sources

- [Listed in CISA KEV notes (support.citrix.com)](https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX693420)
- [CVE.org record CVE-2025-5777](https://www.cve.org/CVERecord?id=CVE-2025-5777)
- [NVD entry CVE-2025-5777](https://nvd.nist.gov/vuln/detail/CVE-2025-5777)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-5777)
- [doublepulsar.com](https://doublepulsar.com/citrixbleed-2-exploitation-started-mid-june-how-to-spot-it-f3106392aa71)
- [reliaquest.com](https://reliaquest.com/blog/threat-spotlight-citrix-bleed-2-vulnerability-in-netscaler-adc-gateway-devices/)
- [bleepingcomputer.com](https://www.bleepingcomputer.com/news/security/cisa-tags-citrix-bleed-2-as-exploited-gives-agencies-a-day-to-patch/)
- [labs.watchtowr.com](https://labs.watchtowr.com/how-much-more-must-we-bleed-citrix-netscaler-memory-disclosure-citrixbleed-2-cve-2025-5777/)
- [theregister.com](https://www.theregister.com/2025/07/10/cisa_citrixbleed_kev/)
- [horizon3.ai](https://horizon3.ai/attack-research/attack-blogs/cve-2025-5777-citrixbleed-2-write-up-maybe/)
- [netscaler.com](https://www.netscaler.com/blog/news/netscaler-critical-security-updates-for-cve-2025-6543-and-cve-2025-5777/)
- [citrixbleed.com](https://citrixbleed.com)

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Source page: https://erroneo.us/security/cve/CVE-2025-5777/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt