CVE-2026-12235— zephyrproject zephyr 缓冲区错误漏洞

Out-of-bounds write in Xtensa llext PLT relocation from malformed ELF (CWE-787)

The Linkable Loadable Extensions (llext) subsystem mis-handles PLT/RELA relocation entries when linking a relocatable (partially-linked) ELF extension. In llext_link_plt() (subsys/llext/llext_link.c), the relocatable branch (tgt != NULL, the path used for Xtensa relocatable objects) computed the patch address as ext->mem[LLEXT_MEM_TEXT] - text.sh_offset + rela.r_offset + tgt->sh_offset and then performed the relocation write there without validating rela.r_offset. Its sibling shared/dynamic branch already rejected out-of-range offsets via llext_file_offset(). rela.r_offset is read directly from the ELF's RELA table, so a crafted entry with an offset larger than the target section makes the write land arbitrarily far outside the extension's text buffer. The result is an attacker-influenced out-of-bounds write (the location via r_offset, the written value being the resolved symbol address) performed in supervisor context at link time, before any extension code runs. The path is reached from llext_load() whenever an application loads an attacker-influenced ELF extension on Xtensa with writable storage; llext is documented to accept extensions of untrusted origin. Impact is supervisor-context memory corruption (integrity and availability loss, and a sandbox-boundary escape for user-mode extensions). Exploitation is gated by the Xtensa relocatable PLT path and writable storage, and turning the out-of-range write into a useful primitive is non-trivial. The fix adds a bound check rejecting any RELA entry whose r_offset >= tgt->sh_size, mirroring the existing validation in the shared branch.

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H

跨界内存写

zephyrproject zephyr 缓冲区错误漏洞

zephyrproject zephyr是zephyrproject组织开源的一个面向物联网设备的实时操作系统。 zephyrproject zephyr 3.7.0版本至4.4.2之前版本存在缓冲区错误漏洞，该漏洞源于llext子系统错误处理PLT/RELA重定位条目，未验证rela.r_offset，可能导致越界写入，进而造成内存破坏（完整性及可用性损失，并可能导致沙箱逃逸）。

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