CVE-2026-19548 in Red Hat
Summary
by MITRE • 08/12/2026
Multiple Use-After-Free vulnerabilities were found in the add_archive_element function in ld/ldmain.c of the GNU linker (ld), a component of binutils. The root cause is that plugin_maybe_claim() in ld/plugin.c frees the original BFD object via bfd_close/_bfd_delete_bfd when entry->the_bfd->my_archive == NULL, but the caller retains both the original abfd parameter and a shallow copy (orig_input.the_bfd) as dangling pointers. These dangling pointers are subsequently dereferenced at three distinct locations in add_archive_element:
1. Line ~1442: accessing abfd->my_archive via bfd_usrdata(abfd->my_archive) 2. Line ~1493: multiple accesses to abfd and abfd->my_archive in a conditional check and bfd_get_filename call 3. Line ~1525: dereferencing the shallow copy orig_input.the_bfd->my_archive in trace/verbose logging
The vulnerability is triggered when LTO plugins are active (link_info.lto_plugin_active is true) and the input object has abfd->my_archive == NULL, which is a valid state for standalone object files. Red Hat builds binutils with --enable-plugins and --enable-lto, confirming the vulnerable code path is compiled in and reachable.
An attacker who can supply a crafted object or archive file to a build process using LTO-enabled linking could exploit this flaw to cause a denial of service (linker crash via segmentation fault). Arbitrary code execution is theoretically possible through heap manipulation but is substantially mitigated by hardening measures including stack protector, FORTIFY_SOURCE, ASLR, and PIE.
The attack surface is limited to build-time environments — the linker is a development tool not exposed in production runtime. The most realistic exploitation scenario is a supply chain attack introducing a crafted object file as a build dependency in CI/CD pipelines or development environments.
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Analysis
by VulDB Data Team • 08/12/2026
Multiple use-after-free vulnerabilities exist in the GNU linker component of binutils within the add_archive_element function located in ld/ldmain.c. This flaw stems from improper handling of BFD objects when plugin_maybe_claim() in ld/plugin.c frees the original BFD object through bfd_close or _bfd_delete_bfd when entry->the_bfd->my_archive equals NULL. The problematic behavior occurs because the caller maintains both the original abfd parameter and a shallow copy (orig_input.the_bfd) as dangling pointers that subsequently get dereferenced at three separate locations in add_archive_element. These memory access violations manifest at line ~1442 where bfd_usrdata(abfd->my_archive) is accessed, at line ~1493 through multiple conditional checks involving abfd and abfd->my_archive followed by bfd_get_filename calls, and finally at line ~1525 when the shallow copy orig_input.the_bfd->my_archive is dereferenced during trace or verbose logging operations. The vulnerability activates specifically when LTO plugins are enabled (link_info.lto_plugin_active equals true) and input objects have abfd->my_archive equal to NULL, which represents a legitimate state for standalone object files rather than corrupted data conditions. Given that Red Hat builds binutils with both --enable-plugins and --enable-lto flags, the vulnerable code path is compiled into production binaries and remains reachable through normal operation sequences.
The technical exploitation of this vulnerability requires an attacker to provide a maliciously crafted object or archive file to a build process utilizing LTO-enabled linking capabilities. Under these circumstances, successful exploitation results in denial of service conditions manifesting as linker crashes through segmentation faults rather than more severe memory corruption issues. While theoretical arbitrary code execution remains possible through sophisticated heap manipulation techniques, practical exploitation faces substantial barriers imposed by modern security mitigations including stack canaries, FORTIFY_SOURCE protections, address space layout randomization, and position-independent executables. The vulnerability operates exclusively within build-time environments since the linker serves as a development tool rather than a runtime component exposed in production systems. Attackers would need to compromise build environments through supply chain infiltration methods, introducing crafted object files as dependencies within continuous integration and deployment pipelines or developer workstations.
The operational impact of this vulnerability extends beyond immediate denial of service scenarios to encompass potential disruption of software development workflows and CI/CD pipeline integrity. Attackers could systematically target build infrastructure by injecting malicious artifacts that trigger these use-after-free conditions during compilation phases, leading to build failures and project delays. The limited attack surface means exploitation requires access to build environments rather than public-facing applications, making this vulnerability more suitable for targeted supply chain attacks against development ecosystems. However, the presence of multiple memory corruption vectors within a single function increases the likelihood of successful exploitation attempts when combined with other vulnerabilities or through social engineering approaches that gain access to developer environments. Security teams should prioritize monitoring and protecting build infrastructure, implementing strict artifact validation procedures, and maintaining up-to-date binutils installations to mitigate this class of vulnerability. This issue aligns with CWE-416 for use-after-free conditions and represents a potential entry point for attackers seeking to establish persistent presence within development ecosystems through supply chain compromise techniques.
The remediation approach requires addressing the core memory management flaw in ld/plugin.c where plugin_maybe_claim() frees BFD objects without properly invalidating all references to them. The fix involves ensuring that all dangling pointer references are eliminated or properly handled before object deallocation occurs, particularly concerning the abfd parameter and shallow copy orig_input.the_bfd. Security hardening measures should include enhanced input validation for object files processed by the linker, implementation of proper reference counting mechanisms, and consideration of memory safety improvements in plugin architecture design. Organizations should implement automated build environment monitoring to detect unusual linking behaviors and maintain regular patching schedules for binutils components. The vulnerability demonstrates the importance of careful memory management in complex software toolchains and highlights the need for comprehensive security testing of development tools that are integral to software compilation processes. Additionally, implementing proper defensive programming practices such as using safe string operations and validating all pointer dereferences can significantly reduce the risk of similar vulnerabilities occurring in future releases.