CVE-2026-43331— x86/kexec: Disable KCOV instrumentation after load_segments()
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I. Basic Information for CVE-2026-43331
Vulnerability Information
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Vulnerability Title
x86/kexec: Disable KCOV instrumentation after load_segments()
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: x86/kexec: Disable KCOV instrumentation after load_segments() The load_segments() function changes segment registers, invalidating GS base (which KCOV relies on for per-cpu data). When CONFIG_KCOV is enabled, any subsequent instrumented C code call (e.g. native_gdt_invalidate()) begins crashing the kernel in an endless loop. To reproduce the problem, it's sufficient to do kexec on a KCOV-instrumented kernel: $ kexec -l /boot/otherKernel $ kexec -e The real-world context for this problem is enabling crash dump collection in syzkaller. For this, the tool loads a panic kernel before fuzzing and then calls makedumpfile after the panic. This workflow requires both CONFIG_KEXEC and CONFIG_KCOV to be enabled simultaneously. Adding safeguards directly to the KCOV fast-path (__sanitizer_cov_trace_pc()) is also undesirable as it would introduce an extra performance overhead. Disabling instrumentation for the individual functions would be too fragile, so disable KCOV instrumentation for the entire machine_kexec_64.c and physaddr.c. If coverage-guided fuzzing ever needs these components in the future, other approaches should be considered. The problem is not relevant for 32 bit kernels as CONFIG_KCOV is not supported there. [ bp: Space out comment for better readability. ]
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于x86 kexec中load_segments后KCOV检测失效，GS基址无效导致内核崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-43331
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Same Patch Batch · Linux · 2026-05-08 · 199 CVEs total
| CVE-2026-43304 | 9.8 CRITICAL | libceph: define and enforce CEPH_MAX_KEY_LEN |
| CVE-2026-43341 | 9.8 CRITICAL | net/ipv6: ioam6: prevent schema length wraparound in trace fill |
| CVE-2026-43376 | 9.8 CRITICAL | ksmbd: fix use-after-free by using call_rcu() for oplock_info |
| CVE-2026-43379 | 9.8 CRITICAL | ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close() |
| CVE-2026-43384 | 9.8 CRITICAL | net/tcp-ao: Fix MAC comparison to be constant-time |
| CVE-2026-43465 | 9.8 CRITICAL | net/mlx5e: RX, Fix XDP multi-buf frag counting for striding RQ |
| CVE-2026-43402 | 9.8 CRITICAL | kthread: consolidate kthread exit paths to prevent use-after-free |
| CVE-2026-43414 | 9.8 CRITICAL | scsi: qla2xxx: Completely fix fcport double free |
| CVE-2026-43383 | 9.4 CRITICAL | net/tcp-md5: Fix MAC comparison to be constant-time |
| CVE-2026-43406 | 9.1 CRITICAL | libceph: prevent potential out-of-bounds reads in process_message_header() |
| CVE-2026-43407 | 9.1 CRITICAL | libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply() |
| CVE-2026-43284 | 8.8 HIGH | xfrm: esp: avoid in-place decrypt on shared skb frags |
| CVE-2026-43322 | 8.8 HIGH | Bluetooth: hci_sync: Fix UAF in le_read_features_complete |
| CVE-2026-43334 | 8.8 HIGH | Bluetooth: SMP: force responder MITM requirements before building the pairing response |
| CVE-2026-43391 | 8.8 HIGH | nsfs: tighten permission checks for handle opening |
| CVE-2026-43403 | 8.8 HIGH | nsfs: tighten permission checks for ns iteration ioctls |
| CVE-2026-43291 | 8.3 HIGH | net: nfc: nci: Fix parameter validation for packet data |
| CVE-2026-43466 | 8.2 HIGH | net/mlx5e: Fix DMA FIFO desync on error CQE SQ recovery |
| CVE-2026-43452 | 8.2 HIGH | netfilter: x_tables: guard option walkers against 1-byte tail reads |
| CVE-2026-43365 | 8.2 HIGH | xfs: fix undersized l_iclog_roundoff values |
Showing top 20 of 199 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
- CVE-2026-43500
rxrpc: Also unshare DATA/RESPONSE packets when paged frags a - CVE-2026-43475
scsi: storvsc: Fix scheduling while atomic on PREEMPT_RT - CVE-2026-43474
fs: init flags_valid before calling vfs_fileattr_get - CVE-2026-43473
scsi: mpi3mr: Add NULL checks when resetting request and rep - CVE-2026-43472
unshare: fix unshare_fs() handling
Same vendor: Linux
- CVE-2026-43500
rxrpc: Also unshare DATA/RESPONSE packets when paged frags a - CVE-2026-43475
scsi: storvsc: Fix scheduling while atomic on PREEMPT_RT - CVE-2026-43474
fs: init flags_valid before calling vfs_fileattr_get - CVE-2026-43473
scsi: mpi3mr: Add NULL checks when resetting request and rep - CVE-2026-43472
unshare: fix unshare_fs() handling
V. Comments for CVE-2026-43331
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