Medium [CVE-2026-19548] Multiple Use-After-Free in add_archive_element via LTO plugin processing
This medium-severity Red Hat Linux advisory covers CVE-2026-19548 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
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).
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- Build environments should avoid running LTO-enabled linking (ld with plugin support) against untrusted or externally-supplied object and archive files. The linker is a build-time tool, not present in production runtimes, so the realistic exposure is to CI/CD pipelines and developer workstations that build from untrusted or externally-contributed sources (supply-chain style attack). Standard hardening measures (ASLR, stack protector, FORTIFY_SOURCE, PIE) substantially reduce the likelihood of arbitrary code execution via heap manipulation, limiting the more realistic impact to a linker crash (denial of service).
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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