CVE-2026-47874: The vulnerability occurs when a client sends HTTP/1.1 pipelined requests over a single connection, causing the

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-47874 is a medium-severity flaw (CVSS 5.3) affecting reactor netty. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The vulnerability occurs when a client sends HTTP/1.1 pipelined requests over a single connection, causing the Reactor Netty HTTP server to consume an excessive amount of memory. Reactor Netty 1.3.0 - 1.3.6 Reactor Netty 1.1.0 - 1.2.18 Reactor Netty 1.0.52 and earlier

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-08-27
Last modified	2026-09-02

Publisher (CNA): VMware · Vendor: pivotal

Last updated 2026-09-02 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-27 01:17 UTCPublished CVE record published
2026-09-02 15:50 UTCUpdated Record last modified

pivotal reactor netty UPGRADE

Affected: < 1.0.53 · >= 1.1.0 and < 1.2.19 · >= 1.3.0 and < 1.3.6.1

Fixed in: 1.0.53, 1.2.19, 1.3.6.1

Safe to downgrade to: a release before 1.1.0

1. Check installed version

apt-cache policy reactor-netty || rpm -q reactor-netty || reactor-netty --version

2. UPGRADE to 1.0.53 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade reactor-netty

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade reactor-netty

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.1.0 (Debian / Ubuntu)

apt-cache madison reactor-netty sudo apt install reactor-netty=<VERSION_BEFORE_1.1.0> sudo apt-mark hold reactor-netty

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list reactor-netty sudo dnf downgrade reactor-netty-<VERSION_BEFORE_1.1.0> sudo dnf versionlock add reactor-netty

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.

Advisories and coverage

Official advisories

Spring Security Advisories: cve-2026-47874 - MEDIUM - Reactor Netty HTTP Server Denial of Service With Pipelined Requests 2026-08-20

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-2026-47874?

reactor netty: upgrade to 1.0.53, 1.2.19, 1.3.6.1. Exact commands for each OS are on this page.

Is CVE-2026-47874 being exploited?

CVE-2026-47874 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-2026-47874 affect?

CVE-2026-47874 affects reactor netty. Severity is medium (CVSS 5.3). The vulnerability occurs when a client sends HTTP/1.1 pipelined requests over a single connection, causing the Reactor Netty HTTP server to consume an excessive amount of memory. Reactor Netty 1.3.0 - 1.3.6 Reactor Netty 1.1.0 - 1.2.18 Reac

How urgent is CVE-2026-47874?

Priority 32/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-47843 LOW 3.7 UPGRADE In specific scenarios involving multiple clients with different DNS resolver configurations, Reactor Netty may
CVE-2026-47844 MEDIUM 5.3 UPGRADE In specific scenarios, the Reactor Netty HTTP Server may leak exception details across unrelated requests
CVE-2026-47848 MEDIUM 6.1 UPGRADE In specific scenarios involving WebSocket handshake redirects to a different origin, the Reactor Netty WebSock
CVE-2026-47845 MEDIUM 5.3 UPGRADE In specific scenarios, Reactor Netty HTTP Server may incorrectly evaluate the remote IP address when HAProxy P

References

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