Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability
Citrix · NetScaler ADC and NetScaler Gateway
Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow flaw (improper restriction of operations within the bounds of a memory buffer) that allows out-of-bounds memory reads. An unauthenticated remote attacker with network access can trigger a denial of service, requiring no authentication, no user interaction, and only low complexity.
Improper Restriction of Operations within the Bounds of a Memory Buffer in NetScaler ADC and NetScaler Gateway allows Unauthenticated Denial of Service and Out-Of-Bounds Memory Read
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 3/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.How attackers get in
What they do
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 1 day before it was disclosed.
- First seen exploitedVulnCheck KEV evidence1 day before
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
2 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 2ExecutionTA0002
This buffer overflow vulnerability can be exploited to cause a denial of service.
ImpactTA0040
Detection
0 rules for this CVE · 11 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2023-6549 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Hijack Execution FlowT15748 general rules
- Exploiting SetupComplete.cmd CVE-2019-1378hightest
- Potential PrintNightmare Exploitation Attempthightest
- Suspicious Printer Driver Empty Manufacturerhightest
- DLL Execution Via Register-cimprovider.exemediumtest
- Potential Initial Access via DLL Search Order Hijackingmediumtest
- Potential Registry Persistence Attempt Via DbgManagedDebuggermediumtest
- Regsvr32 DLL Execution With Uncommon Extensionmediumtest
- Windows Spooler Service Suspicious Binary Loadinformationaltest
Endpoint Denial of ServiceT14993 general rules
- CVE-2024-49113 Exploitation Attempt - LDAP Nightmarehighexperimental
- LSASS Crash Via Netlogon Stack Buffer Overflow - CVE-2026-41089highexperimental
- Potential Abuse of Linux Magic System Request Keymediumexperimental
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 30, 202629 Oct 2026
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- 44 more on OTX