Ghostscript: reintroduction of .charkeys -dsafer bypass in rhel 8

Overview

A flaw was found in Ghostscript as shipped with Red Hat Enterprise Linux 8. The correction for CVE-2019-14869 was omitted during the rebase from version 9.25 to 9.27, leaving privileged .forceput operations in the .charkeys procedure insufficiently protected. Processing a specially crafted PostScript file may allow an attacker to bypass -dSAFER restrictions and access files outside the permitted paths or execute commands with the permissions of the Ghostscript process.

Affected

• ghostscript
• ghostscript
• ghostscript
• ghostscript (all versions)
• ghostscript

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Workarounds

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

--- CME Mitigation Guidance (2026-10-20) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.

The highest-value action is to eliminate privileged .forceput operations in the .charkeys procedure to enforce -dSAFER sandbox boundaries: upgrade to the fixed Ghostscript builds, which replace .forceput invocations with standard put operations in the /.charkeys procedure in Resource/Init/gs_ttf.ps, closing all 2 injection vectors (crafted PostScript document, malicious TrueType font processing). Until patched, this is a concern on Ghostscript on Linux (RHEL 8) processing untrusted input, such as print or document-conversion services, so Restrict or halt processing of untrusted PostScript documents and TrueType font inputs across document-conversion and printing services that invoke Ghostscript. As a compensating measure, Use auditd to log unauthorized file access attempts and unexpected execve syscalls spawned by the Ghostscript process, Run SELinux in enforcing mode to confine the Ghostscript process to a restricted domain, Use Linux mount and PID namespaces to restrict filesystem and process visibility for Ghostscript execution, Deploy an EDR agent to detect and terminate unexpected shell or child process spawns from Ghostscript, and Use Falco or eBPF runtime security to detect anomalous child process execution and unauthorized file reads. These controls limit blast radius and contain exploitation, but they do not fix the underlying privileged .forceput sandbox bypass — apply the upstream patch to fully remediate.

Highest-impact CME: CME-1002 Audit Subsystem (auditd) (medium)

Vendor advisories

• Red Hat VEX · Important · affected: Red Hat Enterprise Linux 8 · no fix planned: Red Hat Enterprise Linux 8 · updated 2026-10-20 · vex