CVE-2026-56848

nodejs: Node.js: Heap-use-after-free in HTTP/2 handling can lead to denial of service

Published Aug 4, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Description

A flaw in Node.js HTTP/2 handling allows `nghttp2_session_mem_send()` to be called re-entrantly while `nghttp2_session_mem_recv()` is executing, resulting in a heap-use-after-free.

This vulnerability affects Node.js **26.x**, **24.x**, and **22.x**.

Analysis

Technical impact

A flaw in Node.js HTTP/2 handling permits the function nghttp2_session_mem_send() to be invoked again while nghttp2_session_mem_recv() is still executing, causing a heap‑use‑after‑free condition. The memory corruption that results can lead to a denial‑of‑service attack. This vulnerability falls under CWEs 416 and 825, indicating a misuse or flaw in memory management and incorrect default behavior for unauthenticated users.

Affected Systems

Node.js versions 26.x, 24.x, and 22.x are affected. The vulnerability originates in the nodejs:node product and impacts servers or applications that use these Node.js releases and rely on the HTTP/2 protocol.

Risk and Exploitability

The CVSS score of 7.5 classifies the vulnerability as high severity; however, the EPSS score is < 1% and it is not listed in CISA KEV. The likely attack vector is remote, requiring an attacker to send specially crafted HTTP/2 traffic to a Node.js application. Exploitation requires the ability to send multiple concurrent or overlapping HTTP/2 requests that trigger the re‑entrant call. Given the severity and remote nature, timely remediation is recommended.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

nodejs

node

unaffected

Version	Status	Constraints
`26.5.0`	affected	≤ 26.5.0
`24.18.0`	affected	≤ 24.18.0
`22.23.1`	affected	≤ 22.23.1

No data.

Vendor Product Versions

Nodejs

Version	Status	Scheme	Platform
`[26.5.0,26.5.0]`	affected	semver	—
`[24.18.0,24.18.0]`	affected	semver	—
`[22.23.1,22.23.1]`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Node.js to a patched version from the July 2026 security releases as documented on the Node.js blog
If HTTP/2 is not needed in your environment, disable it in your application configuration and server settings to remove the vulnerable path
Ensure that any dependent native modules such as nghttp2 are also updated to their latest patched versions

Generated by OpenCVE AI on August 7, 2026 at 14:21 UTC.

Tracking

Advisories

Source	ID	Title
Debian DLA	DLA-4809-1	nodejs security update
Debian DSA	DSA-6517-1	nodejs security update

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.574% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://nodejs.org/en/blog/vulnerability/july-2026-security-releases
https://nvd.nist.gov/vuln/detail/CVE-2026-56848
https://www.cve.org/CVERecord?id=CVE-2026-56848

History

Aug 7, 2026 12:30 PM Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Title	Node.js HTTP/2 Heap Use‑After‑Free via Re‑entrant Call	nodejs: Node.js: Heap-use-after-free in HTTP/2 handling can lead to denial of service
Weaknesses		CWE-825
References		https://nvd.nist.gov/vuln/detail/CVE-2026-56848 https://www.cve.org/CVERecord?id=CVE-2026-56848
Metrics	threat_severity `None`	cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}` threat_severity `Important`

Aug 5, 2026 10:00 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Nodejs Nodejs nodejs
Vendors & Products		Nodejs Nodejs nodejs

Aug 4, 2026 7:45 PM Title updated View changes

Type	Values Removed	Values Added
Title		Node.js HTTP/2 Heap Use‑After‑Free via Re‑entrant Call

Aug 4, 2026 6:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Aug 4, 2026 4:30 PM Description updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		A flaw in Node.js HTTP/2 handling allows `nghttp2_session_mem_send()` to be called re-entrantly while `nghttp2_session_mem_recv()` is executing, resulting in a heap-use-after-free. This vulnerability affects Node.js 26.x, 24.x, and 22.x.
Weaknesses		CWE-416
References		https://nodejs.org/en/blog/vulnerability/july-2026-security-releases
Metrics		cvssV3_0 `{'score': 7.5, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}`