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CVE-2025-5777

Exploitation: active CVSS 9.3 CRITICAL Ransomware: known use

CVSS base score: 9.3 (Critical) vendor CNA · v4.0

Score assigned by the vendor's own CVE Numbering Authority (CNA); CISA's Vulnrichment program adds a score only when the CNA omits one.

Citrix NetScaler ADC and Gateway Out-of-Bounds Read Vulnerability

Vendor: Citrix   Product: NetScaler ADC and Gateway

Description

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.

Lifecycle Timeline

Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 78 points from 2025-06-21, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 100.0% on 2026-09-18.

Published Applicability

CVE List v5 (CNA container) 4 affected · 0 fixed · 0 not affected

Check whether a specific version is affected →

What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.

Research & News Coverage

DateSourceArticle
2026-07-02 The Hacker News Ransomware Groups Turn to Citrix Bleed 2, BYOVD, and Supply Chain Credentials

Articles from monitored vendor research blogs and security news feeds that specifically mention this CVE. Coverage begins when feed monitoring started; earlier articles are not indexed.

Detection & Exploitation

Scan
Exploit / Pen Test
Host / SIEM
none published

Coverage across public collections only: Nuclei and OpenVAS NVT (scan); Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM); Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by PoC-in-GitHub (CC0) and are not vetted: some are fakes and some are malware. Treat them as evidence that code was published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available under the Open Database License (ODbL) v1.0; its individual Vulnerability Tests are licensed GNU GPL v2.

CISA Assessment (Vulnrichment / SSVC)

active
yes
total
—
9.3 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
CWE-457 — Use of Uninitialized Variable
2025-06-17

KEV Catalog Status

2025-07-10
2025-07-11
Known

Listed By

SourceDateRecord
CISA Vulnrichment 2025-06-17 source record →
CISA KEV 2025-07-10 source record →

Referenced in Advisories

DateAdvisoryIssuer
2025-06-26 2025-022: Severe Vulnerabilities in Citrix Products CERT-EU

Weaponization Timeline — Offensive & Testing Tools

No exploit-tool sightings recorded for this CVE.

Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.

External References