CVE-2026-10037
Description
A flaw was found in OpenJDK. A local attacker with low privileges can exploit a sandbox escape vulnerability in the OpenJDK packages. This occurs because the .jar MIME handlers, when the mailcap package is installed, execute files marked as executable. A malicious sandboxed application can write an executable .jar file to the host file system and trigger its execution, leading to arbitrary code execution outside of the sandbox environment.
Statement
Red Hat products are not affected by this vulnerability. CVE-2026-10037 is a packaging defect specific to Debian/Ubuntu OpenJDK distributions: those distributions ship a desktop MIME handler that, via cautious-launcher and the mailcap application/x-java-archive association, can auto-execute a downloaded .jar file. The fix was delivered in the mailcap package (USN-8518-1), not in OpenJDK source code. Red Hat's OpenJDK RPMs ship only jconsole.desktop, which declares no MimeType and no .jar association, do not depend on or install mailcap, and register no application/x-java-archive handler. The vulnerable code path is therefore not present in any Red Hat OpenJDK build. This was independently confirmed downstream by the Hummingbird team, which resolved both trackers (HUM-3135, HUM-3136) as "Not a Bug / Vulnerable Code not Present."
Mitigation
No mitigation is required: Red Hat products are not affected. Red Hat's OpenJDK packages do not ship the .jar MIME handler, do not depend on the mailcap package, and register no application/x-java-archive association, so the vulnerable code path is not present. Users of Debian/Ubuntu OpenJDK should apply the upstream mailcap fix (USN-8518-1).
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | N/A | 8.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality,Integrity,Availability
Technical Impact: Execute Unauthorized Code or Commands
An attacker could insert malicious functionality into the program by causing the program to download code that the attacker has placed into the untrusted control sphere, such as a malicious web site. This could enable the injection of malware, information exposure by granting excessive privileges or permissions to the untrusted functionality, DOM-based XSS vulnerabilities, stealing user's cookies, open redirect to malware (CWE-601), etc.
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