Node: Time-of-check Time-of-use (TOCTOU) Race Condition (CVE-2026-105481)
Published Last modified Sources: HKCERT, Fortinet PSIRT, Red Hat, pwn.watch, BSI, Msrc Update Guide, OSV, CVE.org
What is affected, what to do
A flaw was found in Node.js. The HTTP Agent keep-alive connection reuse logic can cause a client to treat data that arrived on an idle socket before a new request was sent as the response to that request.
Update Node.js to version 22.23.4.
- Affected
- Node
lte 22.23.3..22.23.3 - Node
lte 24.22.0..24.22.0 - Node
lte 26.12.0..26.12.0
- Node
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Metrics
9.8
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
6.5
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: HKCERT, Fortinet PSIRT, Red Hat, pwn.watch, BSI, Msrc Update Guide, OSV, CVE.org
0.3 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 24.8
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 67.40 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 9.8 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 6.5
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.3 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 24.8
- Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-367
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
A flaw was found in Node.js. The HTTP Agent keep-alive connection reuse logic can cause a client to treat data that arrived on an idle socket before a new request was sent as the response to that request. The guard that destroys idle keep-alive sockets when unexpected data arrives only runs when the event loop polls for I/O. If an unsolicited response is already buffered when the socket is assigned to a new request—for example because the event loop was busy with synchronous work—the guard is cleared without observing the data and the bytes are parsed as the response to the new request. This is an incomplete fix of CVE-2026-48931. A malicious or compromised peer that can write an early response on a reused connection may cause the client to accept unintended response content, affecting integrity and potentially confidentiality of application data.
Source: HKCERT (CC BY 3.0 HK) · HKCERT rating: high, fortinet_rss, redhat_csaf, pwn.watch, BSI WID Portal, BSI CSAF, Microsoft Security Update Guide, OSV (Open Source Vulnerabilities), cvelistv5, NVD (NIST), CVE.org (MITRE)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| nodejs | node |
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| Open Source | Node.js |
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Distribution and container packages (6)
Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.
| Affected versions | Fixed in | ||
|---|---|---|---|
| bitnami | node |
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| bitnami | node-min |
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Vendors and products
Weakness classes (CWE)
CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
Base
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
Entry at MITRE CWE-367
References & sources
- nodejs.orgWednesday, October 21, 2026 Security Releasespwn-watch, web
- pwn.watchpwn.watch: Node2Shell / HTTP2Shell: Brotli RCE (CVE-2026-111497) in Node.js, Python, Envoy and Istio + Node.js October releasespwn-watch
- opensourcemalware.comPython Packages Vulnerable to Node2Shellpwn-watch
- thehackernews.comResearchers Demonstrate Node2Shell RCE Exploit on Node.js Build Using Crafted Brotli Datapwn-watch
- NVD (NIST)CVE-2026-111497 (NVD)pwn-watch
- nodejs.orgNode.js 26.12.1 (Current)pwn-watch
- vercel.comVercel bulletin: Brotli decoder RCEpwn-watch
- imperva.comNode2Shell: From Brotli Data to Remote Code Executionpwn-watch
- aikido.devNode2Shell: Node.js Brotli vulnerability allows remote code execution (CVE-2026-111497)pwn-watch
- github.comOut-of-Bounds Write in Brotli Decompressor (GHSA-3wvj-j6qm-62mr)pwn-watch
- patchtheplanet.orgBrotli vulnerability (CVE-2026-111497)pwn-watch
- aikido.devNode2Shell evolves to HTTP2Shell. Brotli flaw (CVE-2026-111497) blast radius affects many libraries & apps using HTTPs.pwn-watch
- news.ycombinator.comEvolving Threat: http2shell is an RCE in node, Python, and more (discussion)pwn-watch
- Microsoft Security Update GuideGoogle: CVE-2026-111497 Buffer overflow vulnerability in the Brotli decoderpwn-watch
- securityweek.comNode2Shell: Brotli Flaw Triggers Patching Across Microsoft, Node.js, Python Packagespwn-watch
- php.netUpdated PHP Windows builds for Brotli security fixpwn-watch
- bleepingcomputer.comMicrosoft releases emergency .NET patches for critical Brotli flawpwn-watch
- bleepingcomputer.comCritical 'HTTP2Shell' Brotli vulnerability triggers emergency patchespwn-watch
- theregister.comMicrosoft releases emergency .NET security fixes for Google Brotli bugpwn-watch
- cisa.govCISA Adds Two Known Exploited Vulnerabilities to Catalogpwn-watch
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
ReceivedHackerOne
CVSS V3: AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
Weakness type: CWE-367
Description added or changed
Show 5 original changes
Individual changes of this event as published by NVD Type Action Before After Description added —A flaw in Node.js HTTP Agent connection reuse can cause a client to accept as valid a response that was sent before the client has sent the request. This is an incomplete fix of CVE-2026-48931. The guard that destroys idle keep-alive sockets when unexpected data arrives only runs when the event loop polls for I/O. If an unsolicited response has already reached the socket but has not been read yet when the socket is handed to a new request, for example because the event loop was busy with synchronous work, the guard is removed without seeing it and the data is parsed as the response to the new request. This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.CVSS added —AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:NWeakness type (CWE) added —CWE-367Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/105xxx/CVE-2026-105481.json">CVE-2026-105481</a>Reference added —https://nodejs.org/en/blog/vulnerability/october-2026-security-releasesSource identifier: support@hackerone.com
Linked advisories
- Node2Shell CVEsFortinet PSIRT
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-105481"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-105481.svg?lang=en" alt="CVE-2026-105481 – NEOSEC Intel" height="20"></a>