Page generated: 10 Nov 2026, 19:58 UTC
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CVE-2025-6543

Memory overflow vulnerability leading to unintended control flow and Denial of Service in NetScaler ADC and NetScaler Gateway when configured as Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) OR AAA virtual server

CVSS 9.2 (CRITICAL) KEV: KNOWN CATALOG

Attention and evidence

HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
8.4/10
General review priority; not probability

Evidence confidence: Exploitation recorded

Why this priority?
  • Recorded exploitation baseline: +7.00
  • Technical severity: CVSS 9.2: +1.38
  • Fresh EPSS: 10.43%: +0.05

General review priority, not probability, victim count or asset-specific risk. A range covers missing CVSS/EPSS inputs within the current evidence state.

Sources: 22 documents and public datasets.

Hype components

Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100

Sources and documents

The Hacker News
Press · 24 Mar 2026, 07:00 · Citrix Urges Patching Critical NetScaler Flaw Allowing Unauthenticated Data Leaks - The Hacker News
DoublePulsar
Press · 31 Aug 2025, 07:00 · Citrix Netscaler backdoors — Part One — May 2025 activity against governments | by Kevin Beaumont - DoublePulsar
DoublePulsar
Press · 28 Aug 2025, 07:00 · Citrix forgot to tell you CVE-2025–6543 has been used as a zero day since May 2025 - DoublePulsar
The Hacker News
Press · 26 Aug 2025, 07:00 · Citrix Patches Three NetScaler Flaws, Confirms Active Exploitation of CVE-2025-7775 - The Hacker News
Industrial Cyber
Press · 13 Aug 2025, 07:00 · NCSC-NL warns of ongoing cyber threat after Citrix NetScaler exploit targets Dutch critical organizations - Industrial Cyber
See all 22 source documents
The Hacker News
Press · 12 Aug 2025, 07:00 · Dutch NCSC Confirms Active Exploitation of Citrix NetScaler CVE-2025-6543 in Critical Sectors - The Hacker News
CyberSecurityNews
Press · 12 Aug 2025, 07:00 · 7000+ Citrix NetScaler Devices Still Vulnerable to CVE-2025-5777 and CVE-2025-6543 - CyberSecurityNews
Security Affairs
Press · 12 Aug 2025, 07:00 · Dutch NCSC: Citrix NetScaler zero-day breaches critical orgs - Security Affairs
BleepingComputer
Press · 11 Aug 2025, 07:00 · Netherlands: Citrix Netscaler flaw CVE-2025-6543 exploited to breach orgs - BleepingComputer
The Hacker News
Press · 11 Jul 2025, 07:00 · CISA Adds Citrix NetScaler CVE-2025-5777 to KEV Catalog as Active Exploits Target Enterprises - The Hacker News
wiz.io
Press · 06 Jul 2025, 07:00 · Critical vulnerabilities in NetScaler ADC exploited in-the-wild: everything you need to know - wiz.io
watchTowr Labs
Press · 04 Jul 2025, 07:00 · How Much More Must We Bleed? - Citrix NetScaler Memory Disclosure (CitrixBleed 2 CVE-2025-5777) - watchTowr Labs
SecurityWeek
Press · 01 Jul 2025, 07:00 · Thousands of Citrix NetScaler Instances Unpatched Against Exploited Vulnerabilities - SecurityWeek
Help Net Security
Press · 30 Jun 2025, 07:00 · CitrixBleed 2 might be actively exploited (CVE-2025-5777) - Help Net Security
Rapid7
Press · 27 Jun 2025, 07:00 · CVE-2025-6543: Zero Day Exploitation of NetScaler ADC and NetScaler Gateway - Rapid7
Cybersecurity Dive
Press · 27 Jun 2025, 07:00 · Hackers exploiting critical Citrix Netscaler flaw, researchers say - Cybersecurity Dive
SecurityWeek
Press · 26 Jun 2025, 07:00 · Critical Citrix NetScaler Flaw Exploited as Zero-Day - SecurityWeek
BleepingComputer
Press · 25 Jun 2025, 07:00 · Citrix warns of NetScaler vulnerability exploited in DoS attacks - BleepingComputer
Arctic Wolf
Press · 25 Jun 2025, 07:00 · CVE-2025-5777 - Arctic Wolf
CyberScoop
Press · 25 Jun 2025, 07:00 · Citrix users hit by actively exploited zero-day vulnerability - CyberScoop
Help Net Security
Press · 23 Jun 2025, 07:00 · Critical Citrix NetScaler bug fixed, upgrade ASAP! (CVE-2025-5777) - Help Net Security
CCB Belgium
Press · 18 Jun 2025, 07:00 · Warning: Three critical vulnerabilities (CVE-2025-5777, CVE-2025-5349, CVE-2025-6543) impact NetScaler ADC & Gateway, leading to unauthenticated memory overread, unintended control flow and Denial of Service. There is evidence of active exploitation - CCB Belgium

Score evolution

● Hype   ● Reality

Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.

First record: hype 0.0 · reality 8.4 (2026-11-02 15:14). The curve appears once the score changes.

Public exploit evidence

2

Public exploit entries / repo candidates

See 2 repos with metrics
RepositoryStarsForksLanguageUpdated
abrewer251/CVE-2025-6543_CitrixNetScaler_PoC61Python03 Jul 2025, 20:07
lex1010/CVE-2025-654300—30 Jun 2025, 08:02
Evidence context and dated references

Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.

Evidence in context

Confidence in exploitation evidence
Exploitation recorded
Priority basis
Recorded exploitation; CVSS 9.2; EPSS 10.4%
Attention, last 30 days
0 distinct story titles; 0 press documents; 0 publisher domains.
Technical potential
network access, no prior privileges, no user interaction, additional attack conditions.
Observed activity
Exploitation recorded in CISA KEV.
Known scale
Not quantified.
Evidence confidence basis
Trusted exploitation confirmation

Score evaluated: 2026-11-05 13:59:45.560576+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z

Source event timeline
First press mention
18 Jun 2025, 07:00
Published
25 Jun 2025, 12:49
Added to the CISA KEV catalog
30 Jun 2025, 00:00
Latest press mention
24 Mar 2026, 07:00
Score calculated
05 Nov 2026, 13:59
PoCs on GitHub
2 repositories