CyberSecBulletin
CVE-2026-88779Exploited in the wildNVD status: Analyzed

Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer

Published Updated By the CyberSecBulletin desk

CVE-2026-88779 is a high-severity improper restriction of operations within the bounds of a memory buffer vulnerability in ADC from NetScaler, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 14.1-73.41, 13.1-64.28, 14.1-73.41 FIPS as the first without the flaw, so updating ADC to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on October 4, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update ADC to 14.1-73.41 or 13.1-64.28 or 14.1-73.41 FIPS or 13.1-37.282, whichever matches your release line, or a later version.
  2. Update Gateway to 14.1-73.41 or 13.1-64.28, whichever matches your release line, or a later version.
  3. Update Netscaler Application Delivery Controller to 13.1-37.282 or 13.1-64.28 or 14.1-73.41, whichever matches your release line, or a later version.
  4. CISA's required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
  5. Read the advisory on support.citrix.com for workarounds and exact fixed builds.
  6. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
NetScalerADCbefore 14.1-73.41; before 13.1-64.28; before 14.1-73.41 FIPS; before 13.1-37.28214.1-73.41, 13.1-64.28, 14.1-73.41 FIPS, 13.1-37.282
NetScalerGatewaybefore 14.1-73.41; before 13.1-64.2814.1-73.41, 13.1-64.28
CitrixNetscaler Application Delivery Controller13.1 up to, but not including, 13.1-37.282; 13.1 up to, but not including, 13.1-64.28; 14.1 up to, but not including, 14.1-73.41; 14.1-66.68 through 14.1-73.4113.1-37.282, 13.1-64.28, 14.1-73.41
CitrixNetscaler Gateway13.1 up to, but not including, 13.1-64.28; 14.1 up to, but not including, 14.1-73.4113.1-64.28, 14.1-73.41

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA
CVSS 3.17.5HighNVD

Official description

Vulnerability in NetScaler ADC and NetScaler Gateway. This issue affects ADC: before 14.1-73.41, before 13.1-64.28, before 14.1-73.41 FIPS, and before 13.1-37.282; Gateway: before 14.1-73.41 and before 13.1-64.28.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities (CWE-119)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: partial).
  3. Added to CISA's Known Exploited Vulnerabilities catalogue.
  4. Record last changed materially (score, affected products, status or references).
  5. Deadline for US federal agencies to remediate, set by CISA.

References

Third-party and government advisories

Our coverage

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All ADC vulnerabilities

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