CVE-2026-23870: A denial of service vulnerability could be triggered by sending specially crafted HTTP requests to server func

Q: How do I fix CVE-2026-23870?

react-server-dom-parcel: upgrade to newer than 19.2.5; react-server-dom-turbopack: upgrade to newer than 19.2.5; react-server-dom-webpack: upgrade to newer than 19.2.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-23870 being exploited?

CVE-2026-23870 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-23870 affect?

CVE-2026-23870 affects react-server-dom-parcel, react-server-dom-turbopack, react-server-dom-webpack. Severity is high (CVSS 7.5). A denial of service vulnerability could be triggered by sending specially crafted HTTP requests to server function endpoints, this could lead to server crashes, out-of-memory exceptions or excessive CPU usage; affecting the following packag

Q: How urgent is CVE-2026-23870?

Priority 50/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADEUPGRADEUPGRADE

CVE-2026-23870 is a high-severity flaw (CVSS 7.5) affecting react-server-dom-parcel, react-server-dom-turbopack, react-server-dom-webpack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A denial of service vulnerability could be triggered by sending specially crafted HTTP requests to server function endpoints, this could lead to server crashes, out-of-memory exceptions or excessive CPU usage; affecting the following packages: react-server-dom-webpack, react-server-dom-parcel, react-server-dom-turbopack (versions 19.0.0 through 19.0.5, 19.1.0 through 19.1.6, and 19.2.0 through 19.2.5).

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 25%)
CISA exploited list	No
Weakness	CWE-400
Published	2026-05-06
Last modified	2026-10-26

Publisher (CNA): Facebook, Inc. · Vendor: facebook

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-06 17:16 UTCPublished CVE record published
2026-10-26 19:10 UTCUpdated Record last modified

facebook react-server-dom-parcel UPGRADE

Affected: >= 19.0.0 and <= 19.0.5 · >= 19.1.0 and <= 19.1.6 · >= 19.2.0 and <= 19.2.5

Fixed in: newer than 19.2.5

Safe to downgrade to: a release before 19.0.0

1. Check installed version

npm ls react-server-dom-parcel

2. UPGRADE to newer than 19.2.5

npm install react-server-dom-parcel@">19.2.5"

3. If no update is available yet, DOWNGRADE to a release before 19.0.0

npm view react-server-dom-parcel versions npm install react-server-dom-parcel@"<19.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

facebook react-server-dom-turbopack UPGRADE

Affected: >= 19.0.0 and <= 19.0.5 · >= 19.1.0 and <= 19.1.6 · >= 19.2.0 and <= 19.2.5

Fixed in: newer than 19.2.5

Safe to downgrade to: a release before 19.0.0

1. Check installed version

npm ls react-server-dom-turbopack

2. UPGRADE to newer than 19.2.5

npm install react-server-dom-turbopack@">19.2.5"

3. If no update is available yet, DOWNGRADE to a release before 19.0.0

npm view react-server-dom-turbopack versions npm install react-server-dom-turbopack@"<19.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

facebook react-server-dom-webpack UPGRADE

Affected: >= 19.0.0 and <= 19.0.5 · >= 19.1.0 and <= 19.1.6 · >= 19.2.0 and <= 19.2.5

Fixed in: newer than 19.2.5

Safe to downgrade to: a release before 19.0.0

1. Check installed version

npm ls react-server-dom-webpack

2. UPGRADE to newer than 19.2.5

npm install react-server-dom-webpack@">19.2.5"

3. If no update is available yet, DOWNGRADE to a release before 19.0.0

npm view react-server-dom-webpack versions npm install react-server-dom-webpack@"<19.0.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-23870?

react-server-dom-parcel: upgrade to newer than 19.2.5; react-server-dom-turbopack: upgrade to newer than 19.2.5; react-server-dom-webpack: upgrade to newer than 19.2.5. Exact commands for each OS are on this page.

Is CVE-2026-23870 being exploited?

CVE-2026-23870 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-23870 affect?

CVE-2026-23870 affects react-server-dom-parcel, react-server-dom-turbopack, react-server-dom-webpack. Severity is high (CVSS 7.5). A denial of service vulnerability could be triggered by sending specially crafted HTTP requests to server function endpoints, this could lead to server crashes, out-of-memory exceptions or excessive CPU usage; affecting the following packag

How urgent is CVE-2026-23870?

Priority 50/100. High severity; Remotely exploitable, no login, no user action

Software pages

React vulnerabilities · Webpack vulnerabilities

References

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