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CVE.org (no NVD analysis yet)· CNA openjs

CVE-2026-123828: Node.js is vulnerable to a heap buffer overflow in HTTP/2 session.altsvc() via a long origin

MediumCVSS 5.9 · v3.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 23/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.54% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: nodejs node 24.22.3, 26.13.1.

Low priority for now. Upgrade to nodejs node 24.22.3, 26.13.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A one-byte heap buffer overflow in Node.js HTTP/2 Alt-Svc handling lets a remote, unauthenticated attacker corrupt process memory. When an application passes an attacker-controlled value such as a request's :authority header to Http2Session.altsvc(), the AltSvc implementation in src/node_http2.cc allocates a buffer sized to the origin length and then writes it with a null terminator, placing one byte past the end of the allocation. A single request carrying a long but syntactically valid :authority triggers the out-of-bounds write, which aborts the process and serves as a remote heap-corruption primitive. This vulnerability affects Node.js 26.x and 24.x.

Published
Nov 11, 2026
Updated
Nov 12, 2026
EPSS
0.5% · 46th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CNA vs NVD score

NVD
—
CNA · openjs
5.9
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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When you'll hear from us

  • when a new CVE affecting this product is published
  • when a record in your stack enters KEV or is weaponized

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits every 10 minutes on paid plans, on the hour on the free plan.

Your free account also gets you

  • CVE alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools, at most 30 a day (3 a day without an account), an API key and MCP
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Versions reported by the vendor

Affected version ranges reported by the assigning authority (openjs). Independent of NVD's CPE analysis and usually ahead of it.

  • nodejs node

    • 24.0.0 and later · before 24.22.3affected · semver
    • 25.0.0 and later · before 26.13.1affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.21nodejsbefore 22.23.5-r022.23.5-r0
Alpine:v3.23nodejsbefore 24.22.3-r024.22.3-r0
Alpine:v3.24nodejs-currentbefore 26.13.1-r026.13.1-r0
Debian:12nodejsfrom 0—

Same product

nodejs: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-27983An attacker can make the Node.js HTTP/2 server completely unavailable by sending a small amount of HTTP/2 frames packets with a few HTTP/2…
    57Plan
  • CVE-2025-27210An incomplete fix has been identified for CVE-2025-23084 in Node.js, specifically affecting Windows device names like CON, PRN, and AUX.
    34Monitor
  • CVE-2026-123872Node.js is vulnerable to a client certificate authentication bypass via TLS 1.2 renegotiation servername change
    32Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-106073Oct 23, 2026 · A flaw in Node.js Permission Model filesystem enforcement leaves `fs.realpathSync()` without the required read permission checks.
    13Monitor
  • ← EarlierCVE-2026-106074Oct 23, 2026 · A flaw in Node.js `crypto` causes the internal entropy caches used by `crypto.randomUUID()`, `crypto.randomUUIDv7()`, and…
    19Monitor
  • Later →CVE-2026-123829Nov 11, 2026 · Node.js is vulnerable to Permission Model file-name disclosure via recursive fs.watch
    10Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
nodejs node24.22.3Vendor (CNA)
nodejs node26.13.1Vendor (CNA)
alpine:nodejs22.23.5-r0 · Alpine:v3.21Package registry (OSV)
alpine:nodejs-current26.13.1-r0 · Alpine:v3.24Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+2 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Not on record for this CVE: patch commit or PR link · variant or chain candidate.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-122 · Heap-based Buffer Overflow

CVSS vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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