CVE-2026-44576 | Next.js: Cache poisoning in React Server Component responses

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.

Published: 2026-05-13 Last update: 2026-05-14 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-44576 is rated Low Risk (22.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.01%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-44576

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-14 0.01%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44576

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
2.2 2.7 [email protected]

Weakness enumeration for CVE-2026-44576

GitHub Security Advisory for CVE-2026-44576

GHSA-wfc6-r584-vfw7 · Severity: medium · Ecosystem: npm — Next.js vulnerable to cache poisoning in React Server Component responses

Affected software / configurations for CVE-2026-44576

Vendor Product Version Raw CPE
vercel next.js >= 14.2.0, < 15.5.16 cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*
vercel next.js >= 16.0.0, < 16.2.5 cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:*

References for CVE-2026-44576

cvelogic Threat Intelligence