CVE-2026-56848Public exploitNetwork attack vector

Remote process crash via re-entrant HTTP/2 send

Published Aug 4, 2026 · Updated Aug 4, 2026

Use-after-free in Node.js 22.23.1, 24.18.0, and 26.5.0 allows remote attackers to crash HTTP/2 server processes with crafted frames. During nghttp2_session_mem_recv(), the HTTP/2 stream-refusal path calls nghttp2_session_mem_send() re-entrantly and frees heap state still in use. Exposure requires an enabled, network-reachable Node.js HTTP/2 listener; confirmed impact is a process crash and resulting service interrupt.

CVSS severity7.5
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Node.js 22.23.1, 24.18.0, and 26.5.0 allows remote attackers to crash HTTP/2 server processes with crafted frames. During nghttp2_session_mem_recv(), the HTTP/2 stream-refusal path calls nghttp2_session_mem_send() re-entrantly and frees heap state still in use. Exposure requires an enabled, network-reachable Node.js HTTP/2 listener; confirmed impact is a process crash and resulting service interrupt.

The record

CVE
CVE-2026-56848
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
Node.js
Product
Node.js
Classifications
CWE-416, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=22.23.1 <=22.23.1
  2. Affected versionversion=24.18.0 <=24.18.0
  3. Affected versionversion=26.5.0 <=26.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Node.js · Node.jsversion=22.23.1 <=22.23.1; version=24.18.0 <=24.18.0; version=26.5.0 <=26.5.0

Published CVSS scores

7.5HackerOne CNACVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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