erroneo.us
Search all guides⌘K

Security Digest · Vulnerability record · Known exploited

CVE-2025-55182: Meta React Server Components Remote Code Execution Vulnerability

Exploited in the wild (CISA KEV). A pre-authentication remote code execution vulnerability exists in React Server Components versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 including the following packages: react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack.

CISA KEV · added 2025-12-05 CVSS 10.0 Critical EPSS 99.8% · p100.0 Act now

Updated By erroneo.us Security Desk17 references Seen in the digest for Dec 5, 2025, digest for Dec 3, 2025

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

  • Yes, if you run Meta React Server Components. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2025-12-05, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2025-12-12; treat that as the outer limit, not the target. CISA also lists it as known to be used in ransomware campaigns.
  • EPSS 99.8%, percentile 100.0: FIRST’s model estimates a 99.8% chance of exploitation activity in the next 30 days, higher than 100.0% of all scored CVEs (very high). EPSS is a probability, not a verdict.
  • Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
  • Only applies if your dependency tree includes react-server-dom-webpack (npm) >= 19.1.0, < 19.1.2, fixed in 19.1.2; react-server-dom-webpack (npm) = 19.2.0, fixed in 19.2.1; react-server-dom-turbopack (npm) >= 19.1.0, < 19.1.2, fixed in 19.1.2; react-server-dom-turbopack (npm) = 19.2.0, fixed in 19.2.1. Check your lockfile, including transitive dependencies.
  • Editorial verdict: Act now. React2Shell: Unauthenticated RCE in React Server Components — If any server you run renders React Server Components and was not patched in December 2025, treat it as compromised until shown otherwise: patch, redeploy, and rotate its secrets.

What it is

A pre-authentication remote code execution vulnerability exists in React Server Components versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 including the following packages: react-server-dom-parcel, react-server-dom-turbopack, and react-server-dom-webpack. The vulnerable code unsafely deserializes payloads from HTTP requests to Server Function endpoints.

From the GitHub advisory

Impact

There is an unauthenticated remote code execution vulnerability in React Server Components.

We recommend upgrading immediately.

The vulnerability is present in versions 19.0.0, 19.1.0, 19.1.1, and 19.2.0 of: react-server-dom-webpack react-server-dom-parcel react-server-dom-turbopack

Patches

CISA’s summary

Meta React Server Components contains a remote code execution vulnerability that could allow unauthenticated remote code execution by exploiting a flaw in how React decodes payloads sent to React Server Function endpoints. Please note CVE-2025-66478 has been rejected, but it is associated with CVE-2025- 55182.

Weakness type: CWE-502.

Product: Meta React Server Components · Assigned by: Meta · Published: 2025-12-03

Affected and fixed versions

EcosystemPackageVulnerableFirst fixed
npmreact-server-dom-webpack>= 19.1.0, < 19.1.219.1.2
npmreact-server-dom-webpack= 19.2.019.2.1
npmreact-server-dom-turbopack>= 19.1.0, < 19.1.219.1.2
npmreact-server-dom-turbopack= 19.2.019.2.1
npmreact-server-dom-parcel>= 19.1.0, < 19.1.219.1.2
npmreact-server-dom-parcel= 19.2.019.2.1
npmreact-server-dom-turbopack= 19.0.019.0.1
npmreact-server-dom-parcel= 19.0.019.0.1
npmreact-server-dom-webpack= 19.0.019.0.1
VendorProductAffected versions (per CVE record)
Metareact-server-dom-webpack19.0.0 <= 19.0.0, 19.1.0 <= 19.1.1, 19.2.0 <= 19.2.0
Metareact-server-dom-turbopack19.0.0 <= 19.0.0, 19.1.0 <= 19.1.1, 19.2.0 <= 19.2.0
Metareact-server-dom-parcel19.0.0 <= 19.0.0, 19.1.0 <= 19.1.1, 19.2.0 <= 19.2.0

Severity scores

Scored byCVSSScoreVector
Meta3.110 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
GitHub3.110.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
  • Attack vector: network (remotely reachable)
  • Attack complexity: low
  • Privileges required: none (no login)
  • User interaction: none
  • Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

  • CISA KEV: added 2025-12-05; federal due date 2025-12-12. Known ransomware use: Known.
  • CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
  • CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
  • FIRST EPSS (model of 2026-10-21): 99.80% probability of exploitation activity in the next 30 days; percentile 100.0.

Timeline

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vendor and project advisories, patches

  1. Listed in CISA KEV notes (react.dev) react.dev
  2. Listed in CISA KEV notes (github.com) github.com

Vulnerability records

  1. GitHub Advisory GHSA-fv66-9v8q-g76r github.com
  2. CVE.org record CVE-2025-55182 cve.org
  3. NVD entry CVE-2025-55182 nvd.nist.gov

Government

  1. CISA Known Exploited Vulnerabilities catalog entry cisa.gov

Other references from the CVE record and advisory

  1. facebook.com facebook.com
  2. aws.amazon.com aws.amazon.com
  3. openwall.com openwall.com
  4. news.ycombinator.com news.ycombinator.com
  5. github.com github.com
  6. github.com github.com
  7. github.com github.com
  8. github.com github.com
  9. github.com github.com
  10. github.com github.com
  11. github.com github.com

All exploited Meta vulnerabilities · Critical npm advisories · Today’s Security Digest