The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - gcov: use atomic counter updates to fix concurrent access crashes GCC's GCOV instrumentation can merge     global branch counters with loop induction variables as an optimization. In inflate_fast(), the inner copy     loops get transformed so that the GCOV counter value is loaded multiple times to compute the loop base     address, start index, and end bound. Since GCOV counters are global (not per-CPU), concurrent execution on     different CPUs causes the counter to change between loads, producing inconsistent values and out-of-bounds     memory writes. The crash manifests during IPComp (IP Payload Compression) processing when inflate_fast()     runs concurrently on multiple CPUs: BUG: unable to handle page fault for address: ffffd0a3c0902ffa RIP:
    inflate_fast+1431 Call Trace: zlib_inflate __deflate_decompress crypto_comp_decompress ipcomp_decompress     [xfrm_ipcomp] ipcomp_input [xfrm_ipcomp] xfrm_input At the crash point, the compiler generated three loads     from the same global GCOV counter (__gcov0.inflate_fast+216) to compute base, start, and end for an     indexed loop. Another CPU modified the counter between loads, making the values inconsistent - the write     went 3.4 MB past a 65 KB buffer. Add -fprofile-update=prefer-atomic to CFLAGS_GCOV at the global level in     the top-level Makefile, guarded by a try-run compile test. The test compiles a minimal program with and     without -fprofile-update=prefer-atomic using the full KBUILD_CFLAGS, then compares undefined symbols in     the resulting object files. If prefer-atomic introduces new undefined references (such as
    __atomic_fetch_add_8 on i386 or __aarch64_ldadd8_relax on arm64 with outline-atomics), the flag is not     added -- the kernel does not link against libatomic. On architectures where GCC inlines 64-bit atomic     counter updates (x86_64, s390, ...) the test passes and the flag is enabled, preventing the compiler from     merging counters with loop induction variables and fixing the observed concurrent-access crash. On     architectures where the flag would introduce libatomic dependencies, it is silently omitted and behaviour     is no worse than before this patch. Move the CFLAGS_GCOV block from its original position (before the arch     Makefile include) to after the core KBUILD_CFLAGS assignments but before the scripts/Makefile.gcc-plugins     include. This placement ensures the try-run test sees arch-specific flags (-m32, -march=, -mno-outline-     atomics) while avoiding GCC plugin flags (-fplugin=) that would break the test on clean builds when plugin     shared objects do not yet exist. (CVE-2026-63825)

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Linux Distros Unpatched Vulnerability : CVE-2026-63825

critical Nessus Plugin ID 327843

Version 1.9