ADC: Missing Release of Memory after Effective Lifetime
CVE-2026-13474 is a high-severity missing release of memory after effective lifetime 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 72.61, 63.18, 37.272 as the first without the flaw, so updating ADC to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.56% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update ADC to 72.61 or 63.18 or 37.272, whichever matches your release line, or a later version.
- Update Gateway to 72.61 or 63.18, whichever matches your release line, or a later version.
- Update Netscaler Application Delivery Controller to 13.1-37.272 or 13.1-63.18 or 14.1-72.61, whichever matches your release line, or a later version.
- Read the advisory on support.citrix.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| NetScaler | ADC | 14.1 up to, but not including, 72.61; 13.1 up to, but not including, 63.18; 14.1 FIPS up to, but not including, 72.61; 13.1 FIPS and NDcPP up to, but not including, 37.272 | 72.61, 63.18, 37.272 |
| NetScaler | Gateway | 14.1 up to, but not including, 72.61; 13.1 up to, but not including, 63.18 | 72.61, 63.18 |
| Citrix | Netscaler Application Delivery Controller | before 13.1-37.272; 13.1 up to, but not including, 13.1-63.18; 14.1 up to, but not including, 14.1-72.61; 14.1-66.68 | 13.1-37.272, 13.1-63.18, 14.1-72.61 |
| Citrix | Netscaler Gateway | 13.1 up to, but not including, 13.1-63.18; 14.1 up to, but not including, 14.1-72.61 | 13.1-63.18, 14.1-72.61 |
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 system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
Denial of service via malformed HTTP/2 requests in NetScaler ADC and NetScaler Gateway if HTTP/2 is enabled in HTTP Profile and associated with the virtual server (of type LB, CS, VPN) or the service configured on NetScaler
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Release of Memory after Effective Lifetime
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
How developers prevent this class of flaw
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC). To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std
- Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
More Missing Release of Memory after Effective Lifetime vulnerabilities (CWE-401)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in ADC
- 9.5 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Missing Release of Memory after Effective Lifetime vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
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