Out-of-bounds Write Affecting binutils package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
0.3% (22nd percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-BINUTILS-18392458
  • published30 Jul 2026
  • disclosed29 Jul 2026

Introduced: 29 Jul 2026

NewCVE-2026-18220  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

There is no fixed version for Debian:unstable binutils.

NVD Description

Note: Versions mentioned in the description apply only to the upstream binutils package and not the binutils package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

An out-of-bounds write vulnerability was found in the BFD library's DLX ELF backend (bfd/elf32-dlx.c) in GNU binutils. The dlx_rtype_to_howto() function maps ELF relocation types to internal howto structures but fails to perform adequate bounds checking on attacker-controlled relocation type values (via ELF32_R_TYPE(r_info)) before indexing into the dlx_elf_howto_table[] array. The DLX relocation type number space is non-contiguous (basic types 0-6, extended types at 0x10000+), but the default case in the switch statement allows arbitrary index values to reach the array access.

A specially crafted ELF/DLX object file can trigger this out-of-bounds write when processed by any BFD-consuming tool (objdump, readelf, strip, ld, nm, objcopy). The vulnerability has been demonstrated to achieve arbitrary code execution via a File Stream Oriented Programming (FSOP) attack against glibc FILE structures (stderr), redirecting control flow to system().

Attack scenarios include CI/CD pipelines performing automated binary analysis, developer workstations running objdump/readelf on untrusted binaries, automated security scanning or malware analysis tools invoking binutils, and package build systems processing third-party code.

Note: This vulnerability is only exploitable when binutils is built with the DLX backend enabled (typically via --enable-targets=all).

CVSS Base Scores

version 3.1