CVE-2026-59279: The MCP Streamable HTTP server transport (WebFlux and WebMvc variants) does not place any limit on the number

This month

HIGH 7.5REMOTEUPGRADE

CVE-2026-59279 is a high-severity flaw (CVSS 7.5) affecting spring ai. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The MCP Streamable HTTP server transport (WebFlux and WebMvc variants) does not place any limit on the number of sessions it retains, and by default does not require clients to be authenticated. As a result, a remote attacker can cause the server to accumulate an unbounded number of sessions over time, gradually exhausting available memory and ultimately causing a Denial of Service that affects all legitimate clients. Affected versions: Spring AI

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	0.5% (top 54%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-08-21
Last modified	2026-10-16

Publisher (CNA): VMware · Vendor: vmware

Last updated 2026-10-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-21 12:16 UTCPublished CVE record published
2026-10-16 15:10 UTCUpdated Record last modified

vmware spring ai UPGRADE

Affected: >= 2.0.0 and < 2.0.1

Fixed in: 2.0.1

Safe to downgrade to: a release before 2.0.0

1. Check installed version

apt-cache policy spring-ai || rpm -q spring-ai || spring-ai --version

2. UPGRADE to 2.0.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade spring-ai

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade spring-ai

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 2.0.0 (Debian / Ubuntu)

apt-cache madison spring-ai sudo apt install spring-ai=<VERSION_BEFORE_2.0.0> sudo apt-mark hold spring-ai

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

dnf --showduplicates list spring-ai sudo dnf downgrade spring-ai-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add spring-ai

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-2026-59279 - HIGH - Unbounded persistent session allocation via repeated initialize 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-2026-59279?

spring ai: upgrade to 2.0.1. Exact commands for each OS are on this page.

Is CVE-2026-59279 being exploited?

CVE-2026-59279 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-2026-59279 affect?

CVE-2026-59279 affects spring ai. Severity is high (CVSS 7.5). The MCP Streamable HTTP server transport (WebFlux and WebMvc variants) does not place any limit on the number of sessions it retains, and by default does not require clients to be authenticated. As a result, a remote attacker can cause the

How urgent is CVE-2026-59279?

Priority 43/100. High severity; Remotely exploitable, no login, no user action

Software pages

VMware vulnerabilities

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References

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