IronPdf on Linux ARM64: Cleaner.ScanPdf() "undefined symbol: string__declarations" or "GLIBC_2.33 not found"

Overview

Before 2026.11.1, the YARA library that IronPDF bundles for Linux ARM64 was a different build from the one on other platforms, so Cleaner.ScanPdf() can't load its scanner and throws Cleaner scanning function is not working. The inner error depends on the machine's glibc version. Upgrading IronPDF to 2026.11.1 fixes it.

On glibc 2.33 or newer (for example Debian 12 or Ubuntu 22.04):

On older glibc (for example Ubuntu 20.04 or Debian 11):

Environment

• OS: Linux ARM64 (any distribution)
• Hosting: Bare Linux, Docker, ARM64 cloud instances (for example AWS Graviton)
• Language/Runtime: .NET with the IronPdf.Linux.ARM package

Version Metadata

• Version found: 2026.10.3
• Version resolved: 2026.11.1

Cause

The ARM64 libyara.so in releases before 2026.11.1 refers to functions that aren't present and needs a newer glibc, so it fails to load either on the glibc check or on the missing string__declarations symbol. 2026.11.1 ships an ARM64 libyara.so rebuilt from YARA 4.1.1 to match the x64 build, with no missing symbols and a glibc 2.17 requirement.

Solution

1. Recommended: Upgrade IronPDF to 2026.11.1 or later, then run Cleaner.ScanPdf() again.

   dotnet add package IronPdf.Linux.ARM --version 2026.11.1 

2. The upgrade fixes the YARA library only. HTML rendering on Linux ARM64 still needs glibc 2.34 or newer, for example Ubuntu 22.04 or Debian 12. On an older glibc, Cleaner.ScanPdf() works after the upgrade, but rendering doesn't.

Workarounds That Don't Work

• Moving to a newer glibc or base image without upgrading IronPDF: the glibc error changes to the string__declarations error, and the scan still fails.

References

• IronPDF changelog: https://ironpdf.com/changelog/
• IronPDF on Linux: https://ironpdf.com/get-started/linux/