BugZero | Citrix NetScaler BugID NSBASE-20186 - NetScaler might experience memory allocation error...

Citrix NetScaler - Defect ID: NSBASE-20186

NetScaler might experience memory allocation errors and crash when handling HTTP/2 traffic at high load. This behavior is seen with NetScalers Fastly NextGen (Signal Sciences) WAF agent configuration.

Citrix NetScaler - Defect ID: NSBASE-20186

NetScaler might experience memory allocation errors and crash when handling HTTP/2 traffic at high load. This behavior is seen with NetScalers Fastly NextGen (Signal Sciences) WAF agent configuration.

Last updated on April 28th, 2026

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Bug Details

Status: Known

Description

The vendor has published 1 unique mention(s) for this bug: 1. NetScaler might experience memory allocation errors and crash when handling HTTP/2 traffic at high load. This behavior is seen with NetScalers Fastly NextGen (Signal Sciences) WAF agent configuration. Modules: 1. System Latest urls for this bug: 1. https://docs.netscaler.com/en-us/updates?product=NetScaler%20ADC%20%28includes%20NetScaler%20Gateway%29&version=13.1&build=61.25 2. https://docs.netscaler.com/en-us/updates?product=NetScaler%20ADC%20%28includes%20NetScaler%20Gateway%29&version=14.1&build=56.74

Change history

2026-04-28 Added: 13.1 Build 61.25, 14.1 Build 56.74

2026-04-28 Removed: Build 13.1-61.25, Build 14.1-56.74

2026-02-02 Removed: Build 13.1-61.23

2026-01-20 Added: Build 13.1-61.26

2025-12-09 Added: Build 13.1-61.25

2025-12-09 Removed: Build 13.1-61.26

2025-11-13 Removed: Build 14.1-56.71

2025-11-13 Added: Build 13.1-61.23

2025-11-11 Added: Build 14.1-56.74

2025-10-24 Added: Build 14.1-56.71

Top Citrix NetScaler Defects

Defect ID: NSHELP-43138
When a NetScaler Console user belonging to an authorization group with virtual server restrictions applies a StyleBook ConfigPack through the API in asynchronous mode (mode=async), the operation fails with an error. The same operation succeeds from NetScaler Console GUI and API in synchronous mode. A sample authorization error is as follows: User <name> is not authorized to access <virtual server>. Workaround: Submit StyleBook ConfigPack API requests by using synchronous mode (mode=sync).
Defect ID: NSHELP-42562
On the Telemetry Execution Details page under Telemetry > NetScaler Telemetry , NetScaler instances managed using an SNIP address might display error code 3206.
Defect ID: NSLB-12381
When an SSL or GeoDB file is synced by using the GSLB sync mechanism, NetScaler incorrectly displays the status as failure, even though the file synchronization is successful.
Defect ID: NSHELP-42609
The NetScaler packet engine might crash due to a defect in backend TLS 1.3 connection state handling during teardown. On NetScaler SDX platforms with multiple instances, a crash in one instance can also affect other instances sharing the same crypto hardware.
Defect ID: NSHELP-41484
NetScaler might generate the lsof_<hostname> file each time you create a support bundle. However, the system fails to remove these files immediately after the generation process is complete.

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Citrix NetScaler - Defect ID: NSBASE-20186

NetScaler might experience memory allocation errors and crash when handling HTTP/2 traffic at high load. This behavior is seen with NetScalers Fastly NextGen (Signal Sciences) WAF agent configuration.

Citrix NetScaler - Defect ID: NSBASE-20186

NetScaler might experience memory allocation errors and crash when handling HTTP/2 traffic at high load. This behavior is seen with NetScalers Fastly NextGen (Signal Sciences) WAF agent configuration.

Last updated on April 28th, 2026

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Top Citrix NetScaler Defects

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