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Mallory
Low

Next.js weak _rsc cache-busting hash cache poisoning

IdentifiersCVE-2026-44582CWE-444

CVE-2026-44582 is a low-severity cache poisoning vulnerability in Next.js affecting versions from 13.4.6 before 15.5.16 and before 16.2.5. The issue affects React Server Component (RSC) responses in deployments that rely on shared caches that do not sufficiently partition response variants. According to the provided content, the _rsc cache-busting value is weak enough that collisions can occur. Under affected caching conditions, an attacker can induce collisions in this _rsc value and poison cached entries, causing subsequent requests for a given URL to be served an incorrect response variant. The flaw is therefore tied to the interaction between Next.js RSC response handling and intermediary/shared cache behavior rather than a purely client-side issue.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can cause cache poisoning of React Server Component responses. Users requesting a legitimate URL may receive the wrong cached response variant for that URL. Depending on application behavior, this can result in content integrity issues, cross-user response mix-ups, unintended disclosure of variant-specific content, and application malfunction due to clients receiving an RSC payload not intended for their request context.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, reduce exposure by disabling shared caching for affected React Server Component responses or ensuring intermediary caches properly partition variants and honor relevant Vary semantics for RSC-related request differences. Review CDN, reverse proxy, and other shared-cache configurations to prevent cache key collisions across distinct RSC response variants.

Remediation

Patch, then assume compromise.

Upgrade Next.js to a fixed release. The provided content states the vulnerability is fixed in versions 15.5.16 and 16.2.5. Organizations should deploy the appropriate patched version for their supported branch and invalidate any potentially poisoned cache entries after upgrade where shared caches are in use.
PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
VercelNextapplication
VercelNext.Jsapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

3 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.