CVE intelligence and bounded remediation

CVE-2025-64503 — Openprinting Cups-Filters security vulnerability

Medium CVSS 4

cups-filters contains backends, filters, and other software required to get the cups printing service working on operating systems other than macos. In cups-filters prior to 1.28.18, by crafting a PDF file with a large `MediaBox` value, an attacker can cause CUPS-Filter 1.x’s `pdftoraster` tool to write beyond the bounds of an array. First, a PDF with a large `MediaBox` width value causes `header.cupsWidth` to become large. Next, the calculation of `bytesPerLine = (header.cupsBitsPerPixel * header.cupsWidth + 7) / 8` overflows, resulting in a small value. Then, `lineBuf` is allocated with the small `bytesPerLine` size. Finally, `convertLineChunked` calls `writePixel8`, which attempts to write to `lineBuf` outside of its buffer size (out of bounds write). In libcupsfilters, the maintainers found the same `bytesPerLine` multiplication without overflow check, but the provided test case does not cause an overflow there, because the values are different. Commit 50d94ca0f2fa6177613c97c59791bde568631865 contains a patch, which is incorporated into cups-filters version 1.28.18.

Severity
Medium
CVSS
4 (3.1)
Published
2025-11-12
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-787

Affected products

  • openprinting / cups-filters
  • openprinting / libcupsfilters

Matched remediation archetype

Buffer bounds, memory safety, and memory corruption

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Check exposure

  • Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
  • Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
  • Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.

Remediate safely

  • Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
  • Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
  • Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.

Authoritative sources

Complete CVE record and remediation plan

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