CVE-2026-44577: Next.js: Denial of Service in the Image Optimization API

Severity: medium (CVSS 5.9 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-13 · updated 2026-10-26
Weakness: CWE-770

Description

Next.js is a React framework for building full-stack web applications. From 10.0.0 to before 15.5.16 and 16.2.5, when self-hosting Next.js with the default image loader, the Image Optimization API fetches local images entirely into memory without enforcing a maximum size limit. An attacker could cause out-of-memory conditions by requesting large local assets from the /_next/image endpoint that match the images.localPatterns configuration (by default, all patterns are allowed). This vulnerability is fixed in 15.5.16 and 16.2.5.

Affected products

Next.js: from 10.0.0 before 15.5.16; from 16.0.0 before 16.2.5 — fixed in 15.5.16, 16.2.5
Npm Next: from 10.0.0 before 15.5.16; from 16.0.0 before 16.2.5 — fixed in 15.5.16, 16.2.5

How to fix

Upgrade to a fixed version: Next.js 15.5.16, 16.2.5; Npm Next 15.5.16, 16.2.5. Check the vendor advisory for mitigations.

References

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