CVE-2025-7546: GNU Binutils Buffer Overflow Vulnerability

CVE-2025-7546 Overview

A vulnerability has been identified in GNU Binutils 2.45 affecting the bfd_elf_set_group_contents function within the bfd/elf.c file. This out-of-bounds write vulnerability allows a local attacker to manipulate memory beyond allocated boundaries, potentially leading to memory corruption, application crashes, or arbitrary code execution within the context of the affected process.

Critical Impact

Local attackers can exploit this out-of-bounds write vulnerability in GNU Binutils to corrupt memory, crash applications, or potentially execute arbitrary code when processing maliciously crafted ELF files.

Affected Products

• GNU Binutils 2.45

Discovery Timeline

• July 13, 2025 - CVE-2025-7546 published to NVD
• July 30, 2025 - Last updated in NVD database

Technical Details for CVE-2025-7546

Vulnerability Analysis

This vulnerability exists in the ELF (Executable and Linkable Format) handling code within GNU Binutils, specifically in the Binary File Descriptor (BFD) library. The bfd_elf_set_group_contents function in bfd/elf.c fails to properly validate boundaries when processing ELF section group contents.

When a maliciously crafted ELF file with manipulated group section data is processed by tools such as objcopy, strip, ld, or other Binutils utilities, the function writes data beyond the allocated buffer boundaries. This memory corruption can lead to unpredictable behavior including application crashes, denial of service, or in certain scenarios, could be leveraged for code execution.

The vulnerability is classified as CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), indicating that the code performs write operations without adequate bounds checking.

Root Cause

The root cause lies in insufficient boundary validation within the bfd_elf_set_group_contents function. When handling ELF section group contents, the function does not properly verify that write operations remain within the allocated memory bounds. This allows crafted input to trigger writes to unintended memory locations.

Attack Vector

This vulnerability requires local access to exploit. An attacker must have the ability to supply a maliciously crafted ELF binary to one of the affected Binutils utilities. Attack scenarios include:

• A developer or build system processing untrusted object files
• Automated build pipelines that compile or link third-party code
• Security researchers or analysts examining potentially malicious binaries
• Package maintainers processing contributed binary artifacts

The attacker crafts an ELF file with specific group section data designed to trigger the out-of-bounds write condition when the file is processed by vulnerable Binutils components.

Detection Methods for CVE-2025-7546

Indicators of Compromise

• Unexpected crashes or segmentation faults when using Binutils tools (objcopy, strip, ld, objdump, readelf)
• Unusual memory allocation errors or corruption messages during ELF file processing
• Core dump files generated by Binutils utilities processing specific input files

Detection Strategies

• Monitor system logs for crash reports and segmentation faults originating from Binutils executables
• Implement file integrity monitoring on Binutils installation directories to detect unauthorized modifications
• Deploy endpoint detection solutions to identify anomalous behavior from development toolchain components
• Review build system logs for unexpected failures during linking or object file manipulation operations

Monitoring Recommendations

• Enable core dump collection and analysis for Binutils processes in development and CI/CD environments
• Configure application crash monitoring to alert on repeated failures of ld, objcopy, strip, and related utilities
• Implement input validation for untrusted ELF files before processing with Binutils tools

How to Mitigate CVE-2025-7546

Immediate Actions Required

• Apply the official patch (commit 41461010eb7c79fee7a9d5f6209accdaac66cc6b) to your GNU Binutils installation
• Update to a patched version of GNU Binutils when made available by your distribution
• Avoid processing untrusted or unknown ELF files with vulnerable Binutils versions
• Isolate build environments that must process potentially malicious binaries

Patch Information

GNU has released a patch addressing this vulnerability. The fix is available in the Binutils Git repository with commit hash 41461010eb7c79fee7a9d5f6209accdaac66cc6b. Users should apply this patch or update to a version of Binutils that includes this fix.

For detailed patch information, see the Sourceware Git Commit and the Sourceware Bug Report.

Workarounds

• Run Binutils tools in sandboxed or containerized environments when processing untrusted input
• Implement pre-processing validation of ELF files using security scanning tools before passing to Binutils
• Use memory-safe build environments with address sanitizers enabled to detect exploitation attempts
• Restrict access to development toolchains to minimize exposure to potentially malicious files

# Example: Run objcopy in a restricted container environment
docker run --rm -v $(pwd):/work:ro --read-only --security-opt=no-new-privileges binutils-container objcopy /work/input.o /work/output.o

# Build Binutils with address sanitizer for detection
./configure CFLAGS="-fsanitize=address -g" LDFLAGS="-fsanitize=address"
make