binutils: Out-of-bounds write in GNU Binutils 2.45 (CVE-2025-7546) #shorts

Summary

Welcome to SecureCast. In today's episode, we'll discuss CVE-2025-7546, a local buffer overflow vulnerability in GNU Binutils 2.45. An exploit is publicly available, and it affects the ELF group handling function bfd_elf_set_group_contents. Fedora has already issued fixes in versions 41 and 42 to address this critical issue.

Product details

GNU Binutils is a collection of binary tools used for assembling, linking, and manipulating binary files. Version 2.45 introduced a flaw in the implementation of the bfd_elf_set_group_contents function in bfd/elf.c. This vulnerability is present in both the vanilla Binutils and the mingw-binutils packages provided by major Linux distributions.

Vulnerability type summary

CVE-2025-7546 is classified as an out-of-bounds write and memory corruption vulnerability. When malformed data is passed to the ELF group handling routine, an attacker can overwrite memory beyond allocated bounds, leading to unpredictable behavior or code execution on the local host.

Details of the vulnerability

The flaw resides in the function bfd_elf_set_group_contents, which processes group section data in ELF files. By crafting a specially malformed ELF group section, an attacker can trigger an out-of-bounds write. The attack requires local access, since Binutils tools operate on files provided by the user. The vulnerability was assigned CVE-2025-7546 and a public exploit was disclosed soon after discovery. The upstream patch is identified by commit hash 41461010eb7c79fee7a9d5f6209accdaac66cc6b. Fedora backported this fix in version 41 of its mingw-binutils package, and Fedora 42 ships the full critical update for both CVE-2025-7545 and CVE-2025-7546.

Conclusion

In closing, CVE-2025-7546 represents a serious risk to anyone using Binutils 2.45 or affected derivatives. Although exploitation requires local file access, automated attacks or inadvertent misuse of malicious binaries could lead to system compromise. We recommend all users apply the upstream patch or upgrade to fixed versions in their distributions immediately. Stay safe, and thanks for listening to SecureCast.

Watch the full video on YouTube: CVE-2025-7546

Remediation and exploitation details

This chain involves the following actors

  • Local Attacker: authorized user on target host who initiates the exploit

This following systems are involved

  • GNU Binutils 2.45 (collection of binary utilities for creating, modifying and inspecting object files): contains vulnerable function

Attack entry point

  • bfd_elf_set_group_contents: function in bfd/elf.c that copies group section data without proper bounds checking

Remediation actions

System Administrator
Apply commit 41461010eb7c79fee7a9d5f6209accdaac66cc6b to the binutils source tree
GNU Binutils source repository
System Administrator
Upgrade to the patched binutils packages provided in Fedora 41 or Fedora 42
Linux distribution package manager (dnf or yum)

Exploitation actions

out-of-bounds write

Local Attacker
Craft a malicious ELF object file with a specially-crafted .group section header that declares an excessively large group length.
GNU Binutils objcopy
Examples:
  • python3 -c 'print("\x00"*32 + "G").encode()' > bad_group_header.bin
  • objcopy --add-section .group=bad_group_header.bin benign.o crafted.o

heap or stack overflow

Local Attacker
Invoke objcopy or readelf on the crafted file, triggering the bfd_elf_set_group_contents call and writing past the intended buffer.
GNU Binutils objcopy
Examples:
  • objcopy --dump-section .group=/dev/stdout crafted.o
  • readelf --sections crafted.o

memory corruption

Local Attacker
Corrupt adjacent control structures (function pointers or size fields) in memory to prepare for code redirection.
Binutils process memory space
Examples:
  • overwrite relocation table pointer to redirect execution flow
  • modify section index to point at attacker-controlled buffer

local code execution

Local Attacker
Execute a subsequent binutils command or linked loader, causing the process to jump into attacker-provided payload.
GNU Binutils toolchain (ld, nm, objdump)
Examples:
  • ld -r corrupted.o -o final_exploit.o
  • objdump -d final_exploit.o | grep '<your_shellcode>'

Related Content

NOTE: The following related content has not been vetted and may be unsafe.

CVE database technical details

CVE ID
CVE-2025-7546
Description
A vulnerability, which was classified as problematic, has been found in GNU Binutils 2.45. Affected by this issue is the function bfd_elf_set_group_contents of the file bfd/elf.c. The manipulation leads to out-of-bounds write. It is possible to launch the attack on the local host. The exploit has been disclosed to the public and may be used. The name of the patch is 41461010eb7c79fee7a9d5f6209accdaac66cc6b. It is recommended to apply a patch to fix this issue.,Eine problematische Schwachstelle wurde in GNU Binutils 2.45 entdeckt. Hierbei geht es um die Funktion bfd_elf_set_group_contents der Datei bfd/elf.c. Mittels dem Manipulieren mit unbekannten Daten kann eine out-of-bounds write-Schwachstelle ausgenutzt werden. Der Angriff muss lokal passieren. Der Exploit steht zur öffentlichen Verfügung. Der Patch wird als 41461010eb7c79fee7a9d5f6209accdaac66cc6b bezeichnet. Als bestmögliche Massnahme wird Patching empfohlen.
Provider
VulDB
CWE / problem types
Out-of-bounds Write,Memory Corruption
Affected Software Versions
GNU:Binutils:[{'version': '2.45', 'status': 'affected'}]
Date Published
2025-07-13T22:02:07.589Z
Last Updated
2025-07-14T16:00:55.446Z