VulnerabilityAwaiting Analysis

CVE-2026-56848

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.

HIGH 7.5EPSS 0.49%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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**.

CVSS 3.0: 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.49% probability · 41th percentile
CISA KEV: Not listed
Weakness: CWE-416
Source: support@hackerone.com

References

https://nodejs.org/en/blog/vulnerability/july-2026-security-releases

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.