CVE-2026-80662
HighCVSS 7.1Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In the Linux kernel, a vulnerability was found in the CXL subsystem where CXL_HEADERLOG_SIZE was defined as 512 bytes, while the actual Header Log register size in the RAS Capability structure is 64 bytes. This caused an out-of-bounds read (by 448 bytes) during data copying, and in the CPER caller path led to leaking 448 bytes of kernel stack memory into the trace event ring buffer, readable by userspace via tracefs.
Risk Assessment
The vulnerability allows a user with tracefs access to read portions of kernel stack memory, potentially exposing sensitive data (e.g., keys, passwords) or bypassing security mechanisms (ASLR, KASLR). However, it requires local system access and permissions to read trace events.
Recommendation
Immediately update the Linux kernel to a version containing the fix for CVE-2026-80662. If updating is not possible, restrict access to tracefs (e.g., mount with 'noexec' or limit permissions) and monitor logs for unusual events.
Other vulnerabilities in Linux kernel
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- CVE-2026-99258Unknown
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- CVE-2026-99257Unknown
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- CVE-2026-99256Unknown
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- CVE-2026-99251Unknown
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- CVE-2026-99250Unknown
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- CVE-2026-99249Unknown
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- CVE-2026-99248Unknown
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- CVE-2026-99247Unknown
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- CVE-2026-99215Unknown
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Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size The CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58 bytes (CXL_RAS_CAPABILITY_LENGTH); the Header Log occupies the trailing 64 bytes at offset 0x18. CXL_HEADERLOG_SIZE was defined as SZ_512, eight times the actual on-device size. header_log_copy() reads CXL_HEADERLOG_SIZE_U32 (128) dwords from the RAS capability iomap, overrunning the 88-byte mapping by 448 bytes. The cxl_aer_uncorrectable_error trace event memcpy()s CXL_HEADERLOG_SIZE (512) bytes from its source. For the CPER caller the source is struct cxl_ras_capability_regs::header_log[16] (64 bytes) embedded in a stack-local cxl_cper_prot_err_work_data, so the memcpy reads 448 bytes of kernel stack into the trace event ring buffer where userspace can read it via tracefs. Set CXL_HEADERLOG_SIZE to 64 and derive CXL_HEADERLOG_SIZE_U32 from it, bringing all iomap readers into agreement on 16 dwords. Userspace tools such as rasdaemon have grown a dependency on the buggy 512-byte (128 u32) header_log layout in the cxl_aer_uncorrectable_error trace event. Add CXL_HEADERLOG_TRACE_SIZE_U32 = 128 and use it for the trace event __array and its memcpy to preserve that ABI. Both callers now pass a zero-filled u32[CXL_HEADERLOG_TRACE_SIZE_U32] staging buffer with only the first CXL_HEADERLOG_SIZE_U32 (16) entries populated from hardware; the remaining 112 u32s are zero-padded, keeping the 512-byte trace ring buffer layout intact. [ dj: Replaced 64 with SZ_64 per RichardC ]
Vulnerability data from NVD (NIST) · CISA KEV · EPSS