CVE-2026-13474: Denial of service via malformed HTTP/2 requests

16

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.6% (30-day exploitation probability)+7
Technical severity (high)+6
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.56%

ahead of 45% of scored CVEs · Oct 14, 2026

Affects

Citrix

Netscaler Application Delivery Controller and 3 more

CVSS base

7.5

High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Citrix Netscaler Application Delivery Controller, Citrix Netscaler Gateway, NetScaler ADC…).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Citrix	Netscaler Application Delivery Controller	< 13.1-37.272≥ 13.1 and < 13.1-63.18≥ 14.1 and < 14.1-72.61version 14.1-66.68	Vulnerable	NIST National Vulnerability Database
Citrix	Netscaler Gateway	≥ 13.1 and < 13.1-63.18≥ 14.1 and < 14.1-72.61	Vulnerable	NIST National Vulnerability Database
NetScaler	ADC	≥ 14.1 and < 72.61≥ 13.1 and < 63.18≥ 14.1 FIPS and < 72.61≥ 13.1 FIPS and NDcPP and < 37.272	Vulnerable	CVE Program (cve.org) e CISA ADP
NetScaler	Gateway	≥ 14.1 and < 72.61≥ 13.1 and < 63.18	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.7	CVSS 4.0	High	—	—	50a63c94-1ea7-4568-8c11-eb79e7c5a2b5 via NIST National Vulnerability Database
8.7	CVSS 4.0	High	—	—	NetScaler via CVE Program (cve.org) e CISA ADP
7.5	CVSS 3.1	High	3.9	3.6	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-401 · Missing Release of Memory after Effective Lifetime

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.56%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · netscaler/adc, netscaler/gateway
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 7.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 30, 2026 · NetScaler

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

support.citrix.com/support-home/kbsearch/article
Vendor Advisory, NIST National Vulnerability Database

Elsewhere on this site

Citrix
every CVE for this vendor

Memory corruption
same class

CWE-401
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-107406 Memory overflow vulnerability leading to Remote Code Execution or Denial of Service 7d
High CVE-2026-88779 Citrix NetScaler Improper Restriction of Operations within the Bounds of a Memory Buffer Vulnerability KEV 11d
High CVE-2026-88778 Predictable exact value from previous values vulnerability in Citrix NetScaler ADC and… 18d
Critical CVE-2026-88776 Buffer Errors (Improper Restriction of Operations within Memory Bounds) in Citrix Netscaler Application Delivery Controller 18d
Critical CVE-2026-88777 Buffer Errors (Improper Restriction of Operations within Memory Bounds) in Citrix Netscaler Application Delivery Controller 18d
High CVE-2026-88774 Improper Input Validation in Citrix Netscaler Application Delivery Controller 18d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-13474 is "Denial of service via malformed HTTP/2 requests", rated High. It affects Netscaler Application Delivery Controller (Citrix); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.56% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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