CVE-2026-44576

Description

Next.js is a React framework for building full-stack web applications. From 14.2.0 to before 15.5.16 and 16.2.5, applications using React Server Components can be vulnerable to cache poisoning when shared caches do not correctly partition response variants. Under affected conditions, an attacker can cause an RSC response to be served from the original URL and poison shared cache entries so later visitors receive component payloads instead of the expected HTML. This vulnerability is fixed in 15.5.16 and 16.2.5.

CVSS v3.1 Score

5.4

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:L

EPSS — Exploit Prediction

0.0002

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-436 CWE-436

Affected Products

Vendor	Product	Versions
vercel	next.js	14.2.0 — 15.5.16
vercel	next.js	16.0.0 — 16.2.5

References

Advisories & Patches

https://github.com/vercel/next.js/security/advisories/GHSA-wfc6-r584-vfw7

Frequently Asked Questions

What is CVE-2026-44576? +

Next.js is a React framework for building full-stack web applications. From 14.2.0 to before 15.5.16 and 16.2.5, applications using React Server Components can be vulnerable to cache poisoning when shared caches do not correctly partition response variants. Under affected conditions, an attacker can cause an RSC response to be served from the original URL and poison shared cache entries so later visitors receive component payloads instead of the expected HTML. This vulnerability is fixed in 15.5.16 and 16.2.5. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2026-44576? +

CVE-2026-44576 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0002, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-44576? +

CVE-2026-44576 affects products from vercel, specifically: next.js. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-44576? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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