VulnerabilityPublished 20 Mar 2026

CVE-2026-33011: nestjs nest · Always-Incorrect Control Flow Implementation

Affects nestjs nestSource CVE Database V5

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Not known to be exploited · CVSS 8.7 High : upgrade to 11.1.16 soon.

Data as of 31 Oct 2026, 20:20 UTC

CVSS 4.0 base score

8.7High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 11.1.16

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 31 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade nestjs nest to 11.1.16.

Affected software

Product	Affected	Fixed in
nestjsnest	Affected <11.1.16	Fixed in 11.1.16

AI-suggested

The primary mitigation is to upgrade all affected NestJS applications to version 11.1.16 or later, where the issue is fixed. Until upgrade is possible, organizations should consider implementing additional request validation at the handler level to detect and reject unexpected HEAD requests or enforce middleware logic explicitly for HEAD requests. Reviewing and hardening middleware to ensure critical security checks cannot be bypassed by HTTP method manipulation is recommended. Network-level controls such as Web Application Firewalls (WAFs) can be configured to block or monitor suspicious HEAD requests targeting GET endpoints. Application logging should be enhanced to detect anomalies in request methods and response patterns. Developers should audit their use of Fastify and NestJS middleware to understand the impact of this control flow bypass and refactor code to minimize reliance on middleware for critical security enforcement. Finally, organizations should monitor security advisories for any emerging exploits and apply patches promptly.

Description

Nest is a framework for building scalable Node.js server-side applications. In versions 11.1.15 and below, a NestJS application using @nestjs/platform-fastify GET middleware can be bypassed because Fastify automatically redirects HEAD requests to the corresponding GET handlers (if they exist). As a result: middleware will be completely skipped, the HTTP response won't include a body (since the response is truncated when redirecting a HEAD request to a GET handler), and the actual handler will still be executed. This issue is fixed in version 11.1.16.

Impact

This vulnerability can have significant impacts on organizations using affected NestJS versions with Fastify. Middleware often enforces critical security controls such as authentication, authorization, input validation, logging, and rate limiting. Bypassing middleware allows attackers to circumvent these protections, potentially gaining unauthorized access, executing unauthorized actions, or evading detection. The vulnerability affects the confidentiality and integrity of applications by allowing unauthorized request processing. Availability impact is limited but could arise if attackers exploit the bypass to trigger resource exhaustion or other denial-of-service conditions. Since the vulnerability is remotely exploitable without authentication or user interaction, it poses a high risk to exposed web services. Organizations relying on NestJS for critical backend services, especially those handling sensitive data or performing security checks in middleware, are at elevated risk. The absence of known exploits in the wild suggests limited active exploitation currently, but the high severity and ease of exploitation warrant immediate attention.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 20 Mar 2026, 05:08 UTC

WeaknessesCWE-670

Technical details

References

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