Security Digest · Vulnerability record
CVE-2026-56846: nodejs node vulnerability
A flaw in Node.js HTTP/2 handling can cause HTTP/2 retained header blocks evade maxSessionMemory and enable remote memory exhaustion.
CVSS 7.5 High EPSS 0.5% · p42 Patch this week
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5%, percentile 42: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 42% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Patch this week. Node.js July 2026 Security Releases: HTTP/2 and 11 CVEs — Routine but real: upgrade every supported Node.js line this week, sooner if you terminate HTTP/2 in Node or rely on the Permission Model as a sandbox.
What it is
A flaw in Node.js HTTP/2 handling can cause HTTP/2 retained header blocks evade maxSessionMemory and enable remote memory exhaustion. This vulnerability affects Node.js 24.x and 22.x.
Weakness type: CWE-400.
Product: nodejs node · Assigned by: hackerone · Published: 2026-08-04
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| nodejs | node | 24.18.0 <= 24.18.0, 22.23.1 <= 22.23.1 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| hackerone | 3.0 | 7.5 High | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact partial.
- FIRST EPSS (model of 2026-10-21): 0.50% probability of exploitation activity in the next 30 days; percentile 42.
Timeline
- — erroneo.us brief: Node.js July 2026 Security Releases: HTTP/2 and 11 CVEs
- — CVE record last updated
- — CVE record published by hackerone
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- CVE.org record CVE-2026-56846 cve.org
- NVD entry CVE-2026-56846 nvd.nist.gov
Other references from the CVE record and advisory
- nodejs.org nodejs.org