# CVE-2026-53914: JetBrains Kotlin: Unsafe Deserialization in Kotlin Build Cache Enables Code Execution

> Unsafe deserialization in Kotlin build cache metadata allows attackers to execute arbitrary code, requiring developers to upgrade the compiler.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2026
- **Updated:** 27 Jun 2026
- **Also known as:** CLSA-2026-1793139590, GHSA-r937-wjx7-w2jp

## What is CVE-2026-53914?

CVE-2026-53914 is a medium-severity unsafe deserialization vulnerability in JetBrains Kotlin, published on 26 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In JetBrains Kotlin before 2.4.20 code execution was possible via unsafe deserialization in the build cache metadata

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-53914?

2 open source packages ship an affected version, including org.jetbrains.kotlin:kotlin-gradle-plugin. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.jetbrains.kotlin:kotlin-gradle-plugin` | Maven | All versions | 2.4.20-Beta1 |
| `org.jetbrains.kotlin:kotlin-gradle-plugin` | Maven | All versions | 2.4.20-Beta1 |

Products: Jetbrains Kotlin.

## How do I fix CVE-2026-53914?

Upgrade org.jetbrains.kotlin:kotlin-gradle-plugin to 2.4.20-Beta1 or later.

## Is CVE-2026-53914 being exploited?

There is no known exploitation of CVE-2026-53914 in the wild and no public exploit code.

## Other vulnerabilities in JetBrains Kotlin

- [CVE-2020-15824](https://insights.sbomify.com/CVE-2020-15824/): Privilege escalation in n/a (high 8.8)
- [CVE-2019-10101](https://insights.sbomify.com/CVE-2019-10101/): Other in n/a (high 8.1)
- [CVE-2019-10102](https://insights.sbomify.com/CVE-2019-10102/): Supply chain in n/a (high 8.1)
- [CVE-2019-10103](https://insights.sbomify.com/CVE-2019-10103/): Other in n/a (high 8.1)
- [CVE-2022-24329](https://insights.sbomify.com/CVE-2022-24329/): Improper Locking in JetBrains Kotlin (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53914 and fix it if it is affected.

What it is: CVE-2026-53914 is a medium-severity unsafe deserialization vulnerability in JetBrains Kotlin, published on 26 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53914 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.jetbrains.kotlin:kotlin-gradle-plugin (Maven): affected all versions; fixed in 2.4.20-Beta1
- org.jetbrains.kotlin:kotlin-gradle-plugin (Maven): affected all versions; fixed in 2.4.20-Beta1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53914/ (Markdown: https://insights.sbomify.com/CVE-2026-53914/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53914
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53914
- OSV: https://osv.dev/vulnerability/CVE-2026-53914

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-53914/
Summaries are generated and may contain mistakes; the official description above is the record.