Citrix NetScaler ADC/NetScaler Gateway HTTP/3 QUIC buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
10.0$5k-$25k0.43+

Summaryinfo

A vulnerability described as very critical has been identified in Citrix NetScaler ADC and NetScaler Gateway. This affects an unknown part of the component HTTP/3 QUIC. Such manipulation leads to buffer overflow. This vulnerability is listed as CVE-2026-120865. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Citrix NetScaler ADC and NetScaler Gateway (unknown version) and classified as very critical. Affected by this issue is an unknown code block of the component HTTP/3 QUIC. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Memory overflow in HTTP/3 (QUIC) can lead to unpredictable or erroneous behavior or Denial of Service in Citrix NetScaler ADC and Citrix NetScaler Gateway.

The advisory is available at support.citrix.com. This vulnerability is handled as CVE-2026-120865 since 11/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 11/13/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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Vendor

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License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 10.0

VulDB Base Score: 10.0
VulDB Temp Score: 10.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/03/2026 CVE reserved
11/13/2026 +10 days Advisory disclosed
11/13/2026 +0 days VulDB entry created
11/13/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: citrix.com

Advisory: support.citrix.com
Status: Not defined

CNA: NetScaler
CVE: CVE-2026-120865 (🔒)

GCVE (CVE): GCVE-0-2026-120865
GCVE (VulDB): GCVE-100-436658

Entryinfo

Created: 11/13/2026 09:39
Changes: 11/13/2026 09:39 (64)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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