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Vulnerabilities

Vulnerability · CVE-2026-108859

mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sen…

Published Oct 11, 2026 · catalog updated Oct 18, 2026 · the affected product

Open the advisory

Exploitation likelihood is not on this record for CVE-2026-108859. A missing EPSS score is not a low risk. Compare the affected product with the linked advisory before you change production.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
  • EPSS is missing. A missing score is not a low risk.
Severity
High8.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
Awaiting synchronization with FIRST
Remediation
Not established
Affected products
See sources for product scope

mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sending oversized POST bodies. Attackers can send arbitrarily large or many concurrent POST requests, read fully via io.ReadAll before validation, to degrade or OOM-kill the server process.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-108859

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

Exploitation likelihood is not on this record for CVE-2026-108859. A missing EPSS score is not a low risk. Compare the affected product with the linked advisory before you change production.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-770: Allocation of Resources Without Limits or Throttling. EPSS is not on this record yet. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 11, 2026 · NIST NVD

    Detected

    mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sending oversized POST bodies. Attackers can send arbitrarily large or many concurrent POST requests, read fully via io.ReadAll before validation, to degrade or OOM-kill the server process.

  2. Oct 18, 2026 · NIST NVD

    Updated

    mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sending oversized POST bodies. Attackers can send arbitrarily large or many concurrent POST requests, read fully via io.ReadAll before validation, to degrade or OOM-kill the server process.

Sources

  • CVE.orgVulnerability recordCVE-2026-108859

    Official CVE identifier

    cve.org
  • NIST NVDVulnerability recordCVE-2026-108859

    mcp-go through 1.2.1 contains a denial of service vulnerability in StreamableHTTPServer.ServeHTTP that allows remote unauthenticated attackers to exhaust memory by sending oversized POST bodies. Attackers can send arbitrarily large or many concurrent POST requests, read fully via

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.