High severity vulnerability that affects YamlDotNet and YamlDotNet.Signed

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.8 · CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

• CVE-2018-1000210: 1.47% estimated exploitation activity in the next 30 days; percentile 73.77 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

YamlDotNet version 4.3.2 and earlier contains a Insecure Direct Object Reference vulnerability in The default behavior of Deserializer.Deserialize() will deserialize user-controlled types in the line "currentType = Type.GetType(nodeEvent.Tag.Substring(1), throwOnError: false);" and blindly instantiates them. that can result in Code execution in the context of the running process. This attack appear to be exploitable via Victim must parse a specially-crafted YAML file. This vulnerability appears to have been fixed in 5.0.0.

Published by the source

16 Oct 2018, 17:01 UTC

Last modified by the source

9 Jan 2023, 05:03 UTC

Source last checked

26 Oct 2026, 16:58 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rpch-cqj9-h65r

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# Patch Next advisory brief: CVE-2018-1000210

Advisory: High severity vulnerability that affects YamlDotNet and YamlDotNet.Signed
IDs: CVE-2018-1000210, GHSA-rpch-cqj9-h65r
Record: https://patchnext.com/advisories/cve-2018-1000210 (revision 1, source checked 26 Oct 2026, 16:58 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: yamldotnet.signed 5.0.0; yamldotnet 5.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet yamldotnet.signed: affected <= 4.3.2; fixed in 5.0.0
- NuGet yamldotnet: affected <= 4.3.2; fixed in 5.0.0

## Suggested inspection (read-only)
- NuGet yamldotnet.signed: check the installed version with your package manager.
- NuGet yamldotnet: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on yamldotnet.signed, yamldotnet.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-rpch-cqj9-h65r (GitHub-reviewed advisory GHSA-rpch-cqj9-h65r lists affected ranges: NuGet yamldotnet >=0 =0 <=4.3.2)

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