medium CVSS 5.5 EPSS <0.1%

CVE-2021-47428·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: powerpc/64s: fix program check interrupt emergency stack path Emergency stack path was jumping into a 3: label inside the __GEN_COMMON_BODY macro for the normal path after it had finished, rather than jumping over it. By a small miracle this is the correct place to build up a new interrupt frame with the existing stack pointer, so things basically worked okay with an added weird looking 700 trap frame on top (which had the wrong ->nip so it didn't decode bug messages either). Fix this by avoiding using numeric labels when jumping over non-trivial macros. Before: LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: CPU: 0 PID: 88 Comm: sh Not tainted 5.15.0-rc2-00034-ge057cdade6e5 #2637 NIP: 7265677368657265 LR: c00000000006c0c8 CTR: c0000000000097f0 REGS: c0000000fffb3a50 TRAP: 0700 Not tainted MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 00000700 XER: 20040000 CFAR: c0000000000098b0 IRQMASK: 0 GPR00: c00000000006c964 c0000000fffb3cf0 c000000001513800 0000000000000000 GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299 GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8 GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 0000000000000001 GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8 GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158 GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300 GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80 NIP [7265677368657265] 0x7265677368657265 LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10 Call Trace: [c0000000fffb3cf0] [c00000000000bdac] soft_nmi_common+0x13c/0x1d0 (unreliable) --- interrupt: 700 at decrementer_common_virt+0xb8/0x230 NIP: c0000000000098b8 LR: c00000000006c0c8 CTR: c0000000000097f0 REGS: c0000000fffb3d60 TRAP: 0700 Not tainted MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 22424282 XER: 20040000 CFAR: c0000000000098b0 IRQMASK: 0 GPR00: c00000000006c964 0000000000002400 c000000001513800 0000000000000000 GPR04: 0000000048ab0778 0000000042000000 0000000000000000 0000000000001299 GPR08: 000001e447c718ec 0000000022424282 0000000000002710 c00000000006bee8 GPR12: 9000000000009033 c0000000016b0000 00000000000000b0 0000000000000001 GPR16: 0000000000000000 0000000000000002 0000000000000000 0000000000000ff8 GPR20: 0000000000001fff 0000000000000007 0000000000000080 00007fff89d90158 GPR24: 0000000002000000 0000000002000000 0000000000000255 0000000000000300 GPR28: c000000001270000 0000000042000000 0000000048ab0778 c000000080647e80 NIP [c0000000000098b8] decrementer_common_virt+0xb8/0x230 LR [c00000000006c0c8] ___do_page_fault+0x3f8/0xb10 --- interrupt: 700 Instruction dump: XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX ---[ end trace 6d28218e0cc3c949 ]--- After: ------------[ cut here ]------------ kernel BUG at arch/powerpc/kernel/exceptions-64s.S:491! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV Modules linked in: CPU: 0 PID: 88 Comm: login Not tainted 5.15.0-rc2-00034-ge057cdade6e5-dirty #2638 NIP: c0000000000098b8 LR: c00000000006bf04 CTR: c0000000000097f0 REGS: c0000000fffb3d60 TRAP: 0700 Not tainted MSR: 9000000000021031 <SF,HV,ME,IR,DR,LE> CR: 24482227 XER: 00040000 CFAR: c0000000000098b0 IRQMASK: 0 GPR00: c00000000006bf04 0000000000002400 c000000001513800 c000000001271868 GPR04: 00000000100f0d29 0000000042000000 0000000000000007 0000000000000009 GPR08: 00000000100f0d29 0000000024482227 0000000000002710 c000000000181b3c GPR12: 9000000000009033 c0000000016b0000 00000000100f0d29 c000000005b22f00 GPR16: 00000000ffff0000 0000000000000001 0000000000000009 00000000100eed90 GPR20: 00000000100eed90 00000 ---truncated---

Severity
medium
Software
Kernel
Fixed in
5.14.12
Published

How likely is exploitation

FIRST's Exploit Prediction Scoring System puts the probability of this CVE being exploited in the next 30 days at <0.1% — higher than 8% of all published CVEs. EPSS is an independent forecast of exploitation, not a severity rating: it says nothing about how much damage a successful attack does, which is what a CVSS score measures.

Affected versions

From: 5.11

Until: 5.14.12

Fixed in: 5.14.12

How to fix this CVE

Update your Linux kernel to version 5.14.12 or later to resolve this PowerPC interrupt handling vulnerability. The fix corrects improper jump logic in the emergency stack path for program check interrupts on 64-bit PowerPC systems, which previously resulted in malformed stack frames and unreliable crash dumps. Apply the update through your distribution's package manager to restore proper interrupt frame construction.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Check current kernel version: uname -r (affected versions: 5.11–5.14.11)
  2. Verify PowerPC architecture: uname -m (look for 'ppc64' or 'ppc64le')
  3. Review system logs for corrupted stack traces: grep -i 'TRAP: 0700\|program check' /var/log/kern.log or journalctl -xe
  4. Confirm the fix: uname -r should report 5.14.12 or later after updating

FAQ

What is CVE-2021-47428?

CVE-2021-47428 is a PowerPC kernel vulnerability in the program check interrupt emergency stack path that causes incorrect jump-over logic, leading to malformed interrupt frames with corrupted instruction pointers. This makes kernel crash dumps unreliable and difficult to interpret on affected 64-bit PowerPC systems.

Is CVE-2021-47428 being actively exploited?

No, CVE-2021-47428 is not listed in CISA's Known Exploited Vulnerabilities catalog and no public exploits are available. This is a reliability and diagnostics issue rather than a security bypass.

What versions of Kernel are affected by CVE-2021-47428?

Linux kernel versions 5.11 through 5.14.11 on 64-bit PowerPC systems are affected. The fix is included in kernel 5.14.12 and later.

How do I check if my server is vulnerable to CVE-2021-47428?

Run: uname -r && uname -m. If the output shows kernel version 5.11–5.14.11 AND the architecture contains 'ppc64', your system is vulnerable.

Does Defensia detect CVE-2021-47428?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If the Linux kernel is installed on a monitored server running affected versions, CVE-2021-47428 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64268CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: bound Read Response placement to the RREAD length In drivers/infiniband/sw/siw/siw_qp_rx.c, siw_proc_rresp() places each inbound Read Response DDP segment at sge->laddr + wqe->processed and then accumulates wqe->processed, but it never checks the running total against the sink buffer length on continuation segments. siw_check_sge() resolves and validates the sink memory only on the first fragment (the if (!*mem) branch), and siw_rresp_check_ntoh() compares the cumulative length against wqe->bytes only on the final segment (the !frx->more_ddp_segs guard). A connected siw peer that answers an outstanding RREAD with Read Response segments that keep the DDP Last flag clear, carrying more total payload than the RREAD requested, drives wqe->processed past the validated sink buffer; the next siw_rx_data() call writes out of bounds at sge->laddr + wqe->processed. siw runs iWARP over ordinary routable TCP, so the peer is the remote end of an established RDMA connection and needs no local privilege. Bound every segment before placement, exactly as siw_proc_send() and siw_proc_write() already do for their tagged and untagged paths, and terminate the connection with a base-or-bounds DDP error when the Read Response would overrun the sink buffer. This is the second receive-path length fix for this file. A separate change rejects an MPA FPDU length that underflows the per-fragment remainder in the header decode; that guard does not cover this case, because here each individual segment length is self-consistent and only the accumulated placement offset overruns the buffer.
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CVE-2026-53384CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: serial: 8250_dw: unregister 8250 port if clk_notifier_register() fails dw8250_probe() registers the 8250 port via serial8250_register_8250_port() and then, if the device has a clock, registers a clock notifier. If clk_notifier_register() fails, probe returns the error but leaves the 8250 port registered. The matching serial8250_unregister_port() lives in dw8250_remove(), which is not called when probe fails, so the port slot stays occupied until the device is rebound or the system is rebooted. The devm-allocated driver data is freed while the port still references it (via the saved private_data and serial_in/serial_out callbacks), so any access to that port slot before a rebind is a use-after-free hazard. Unregister the port on the clk_notifier_register() error path.

References

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