CVE-2026-21710VulnerabilityPublished 22 Apr 2026Updated 23 Oct 2026

Red Hat Security Advisory: nodejs:20 security update

Affects Red Hat nodejs:20Source GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-21710· High 7.5

Not known to be exploited · 25% EPSS · CVSS 7.5 High · fixed in Red Hat package updates : patch Red Hat node soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.0 base score

7.5High

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

EPSS: 25.4% chance of exploitation in 30 days – higher than 97% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 26.0.0, 25.0.0, 23.0.0 +1

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 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 29 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.

cwe-770

What to do

Upgrade node to 26.0.0, 25.0.0, 23.0.0 or 21.0.0.

Affected software

Product	Affected	Fixed in
nodejsnode	Affected 4.0 – 19.0 >=20.20.1 <=20.20.1 >=22.22.1 <=22.22.1 >=24.14.0 <=24.14.0 >=25.8.1 <=25.8.1 16 affected builds	Fixed in–
npmnode`pkg:npm/node`Other threats	Affected >=20.0.0 <21.0.0 >=22.0.0 <23.0.0 >=24.0.0 <25.0.0 >=25.0.0 <26.0.0	Fixed in 21.0.0 23.0.0 25.0.0 26.0.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Red Hat has released updated Node.js 20 packages (version 20.20.2 and later) that address these vulnerabilities. Users running affected versions (>=20.0.0 <20.20.2) on Red Hat Enterprise Linux 9.6 Extended Update Support should apply the available security update promptly. Detailed update instructions are available in the Red Hat advisory at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated beyond applying the official update.

Description

Node.js is a software development platform for building fast and scalable network applications in the JavaScript programming language. Security Fix(es): * minimatch: minimatch: Denial of Service via specially crafted glob patterns (CVE-2026-26996) * minimatch: Minimatch: Denial of Service via catastrophic backtracking in glob expressions (CVE-2026-27904) * nghttp2: nghttp2: Denial of Service via malformed HTTP/2 frames after session termination (CVE-2026-27135) * Node.js: Node.js: Denial of Service due to crafted HTTP `__proto__` header (CVE-2026-21710) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Impact

The vulnerabilities can cause denial of service conditions in affected Node.js environments, potentially disrupting network applications that rely on Node.js 20. The issues stem from crafted inputs that trigger resource exhaustion or improper handling of protocol frames, leading to service unavailability. No known exploits in the wild have been reported at this time.

Summary

This Red Hat security advisory (RHSA-2026:9874) addresses four denial of service vulnerabilities affecting Node.js 20 and related components. CVE-2026-21710 concerns a denial of service in Node.js caused by a crafted HTTP __proto__ header. CVE-2026-26996 and CVE-2026-27904 involve denial of service in the minimatch library due to specially crafted glob patterns and catastrophic backtracking in glob expressions, respectively. CVE-2026-27135 is a denial of service in nghttp2 triggered by malformed HTTP/2 frames after session termination. The advisory covers Red Hat Enterprise Linux 9.6 Extended Update Support and provides updated packages to fix these issues. The vulnerabilities are rated as having a high severity impact.

CWE-843Access of Resource Using Incompatible Type (Type Confusion) (opens in a new tab)
Base weakness
The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.
CWE-1333Inefficient Regular Expression Complexity (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Architecture and Design
Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
System Configuration
Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
Implementation
Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
Regular Expression Exponential Blowup (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-617Reachable Assertion (opens in a new tab)
Base weakness
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
Implementation
If the assertion statement is required (e.g., for security or reliability), change the invoking code to avoid the conditions that trigger the assertion.
Implementation
Consider changing the assertion to some other less "fatal" error. This might not be easy to implement, since other code may be needed to handle the error.
Implementation
Make sensitive open/close operations non-reachable from directly user-controlled data (e.g. open/close resources)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Aug 2026, 20:26 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-843, CWE-1333, CWE-617

Technical details

References

Community reviews

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