2018 In early January 2018, it was reported that all
Intel processors made since 1995 (besides
Intel Itanium and pre-2013
Intel Atom) have been subject to two security flaws dubbed
Meltdown and
Spectre. The impact on performance resulting from software patches is "workload-dependent". Several procedures to help protect home computers and related devices from the Spectre and Meltdown security vulnerabilities have been published. Spectre patches have been reported to significantly slow down performance, especially on older computers; on the newer 8th-generation Core platforms, benchmark performance drops of 2–14% have been measured. Meltdown patches may also produce performance loss. It is believed that "hundreds of millions" of systems could be affected by these flaws. More security flaws were disclosed on May 3, 2018, on August 14, 2018, on January 18, 2019, and on March 5, 2020. On March 15, 2018, Intel reported that it will redesign its
CPUs (performance losses to be determined) to protect against the
Spectre security vulnerability, and expects to release the newly redesigned processors later in 2018. On May 3, 2018, eight additional Spectre-class flaws were reported. Intel reported that they are preparing new patches to mitigate these flaws. On August 14, 2018, Intel disclosed three additional chip flaws referred to as
L1 Terminal Fault (L1TF). They reported that previously released microcode updates, along with new, pre-release microcode updates can be used to mitigate these flaws.
2019 On January 18, 2019, Intel disclosed three new vulnerabilities affecting all Intel CPUs, named "Fallout", "RIDL", and "ZombieLoad", allowing a program to read information recently written, read data in the line-fill buffers and load ports, and leak information from other processes and virtual machines. Coffee Lake-series CPUs are even more vulnerable, due to hardware mitigations for
Spectre.
2020 On March 5, 2020, computer security experts reported another Intel chip security flaw, besides the
Meltdown and
Spectre flaws, with the systematic name (or "Intel CSME Bug"). This newly found flaw is not fixable with a firmware update, and affects nearly "all Intel chips released in the past five years".
2021 In March 2021 AMD security researchers discovered that the Predictive Store Forwarding algorithm in
Zen 3 CPUs could be used by malicious applications to access data it shouldn't be accessing. According to Phoronix there's little performance impact in disabling the feature. In June 2021, two new vulnerabilities,
Speculative Code Store Bypass (
SCSB, CVE-2021-0086) and
Floating Point Value Injection (FPVI, CVE-2021-0089), affecting
all modern x86-64 CPUs both from Intel and AMD were discovered. In order to mitigate them software has to be rewritten and recompiled. ARM CPUs are not affected by SCSB but some certain ARM architectures are affected by FPVI. Also in June 2021,
MIT researchers revealed the
PACMAN attack on Pointer Authentication Codes (PAC) in
ARM v8.3A. In August 2021 a vulnerability called "
Transient Execution of Non-canonical Accesses" affecting certain AMD CPUs was disclosed. It requires the same mitigations as the MDS vulnerability affecting certain Intel CPUs. It was assigned CVE-2020-12965. Since most x86 software is already patched against MDS and this vulnerability has the exact same mitigations, software vendors don't have to address this vulnerability. In October 2021 for the first time ever a vulnerability similar to Meltdown was disclosed to be affecting all AMD CPUs however the company doesn't think any new mitigations have to be applied and the existing ones are already sufficient.
2022 In March 2022, a new variant of the Spectre vulnerability called
Branch History Injection was disclosed. It affects certain ARM64 CPUs and the following Intel CPU families:
Cascade Lake,
Ice Lake,
Tiger Lake and
Alder Lake. According to Linux kernel developers AMD CPUs are also affected. In March 2022, a vulnerability affecting a wide range of AMD CPUs was disclosed under CVE-2021-26341. In June 2022, multiple
MMIO Intel CPUs vulnerabilities related to execution in
virtual environments were announced. The following CVEs were designated: CVE-2022-21123, CVE-2022-21125, CVE-2022-21166. In July 2022, the
Retbleed vulnerability was disclosed affecting Intel Core 6 to 8th generation CPUs and AMD Zen 1, 1+ and 2 generation CPUs. Newer Intel microarchitectures as well as AMD starting with Zen 3 are not affected. The mitigations for the vulnerability decrease the performance of the affected Intel CPUs by up to 39%, while AMD CPUs lose up to 14%. In August 2022, the
SQUIP vulnerability was disclosed affecting Ryzen 2000–5000 series CPUs. According to AMD the existing mitigations are enough to protect from it. According to a Phoronix review released in October, 2022
Zen 4/
Ryzen 7000 CPUs are not slowed down by mitigations, in fact disabling them leads to a performance loss.
2023 In February 2023 a vulnerability affecting a wide range of AMD CPU architectures called "
Cross-Thread Return Address Predictions" was disclosed. In July 2023 a critical vulnerability in the
Zen 2 AMD microarchitecture called
Zenbleed was made public.AMD released a microcode update to fix it. In August 2023 a vulnerability in AMD's
Zen 1,
Zen 2,
Zen 3, and
Zen 4 microarchitectures called
Inception was revealed and assigned [https://nvd.nist.gov/vuln/detail/CVE-2023-20569 CVE-2023-20569. According to AMD it is not practical but the company released a microcode update for the affected products. vulnerability (
Spectre based on Linear Address Masking) reported in 2023 neither has received a corresponding CVE, nor has been confirmed or mitigated against.
2024 In March 2024, a variant of Spectre-V1 attack called
GhostRace was published. It was claimed it affected all the major microarchitectures and vendors, including Intel, AMD and ARM. It was assigned CVE-2024-2193. AMD dismissed the vulnerability (calling it "Speculative Race Conditions (SRCs)") claiming that existing mitigations were enough. Linux kernel developers chose not to add mitigations citing performance concerns. The
Xen hypervisor project released patches to mitigate the vulnerability but they are not enabled by default. Also in March 2024, a vulnerability in
Intel Atom processors called
Register File Data Sampling (
RFDS) was revealed. It was assigned CVE-2023-28746. Its mitigations incur a slight performance degradation. In April 2024, it was revealed that the BHI vulnerability in certain Intel CPU families could be still exploited in Linux entirely in
user space without using any kernel features or root access despite existing mitigations. Intel recommended "additional software hardening". The attack was assigned CVE-2024-2201. In June 2024,
Samsung Research and
Seoul National University researchers revealed the
TikTag attack against the Memory Tagging Extension in
ARM v8.5A CPUs. The researchers created PoCs for
Google Chrome and the
Linux kernel. Researchers from VUSec previously revealed ARM's Memory Tagging Extension is vulnerable to speculative probing. In July 2024,
UC San Diego researchers revealed the
Indirector attack against
Intel Alder Lake and
Raptor Lake CPUs leveraging high-precision Branch Target Injection (BTI). Intel downplayed the severity of the vulnerability and claimed the existing mitigations are enough to tackle the issue. No CVE was assigned.
2025 In January 2025, Georgia Institute of Technology researchers published two whitepapers on
Data Speculation Attacks via Load Address Prediction on Apple Silicon (SLAP) and Breaking the Apple M3 CPU via False Load Output Predictions (FLOP). Also in January 2025,
ARM disclosed a vulnerability () in which an unprivileged context can trigger a data memory-dependent
prefetch engine to fetch data from a privileged location, potentially leading to unauthorized access. To mitigate the issue, Arm recommends disabling the affected prefetcher by setting CPUACTLR6_EL1[41]. In May 2025, VUSec released three vulnerabilities extending on Spectre-v2 in various Intel and ARM architectures under the moniker
Training Solo. Mitigations require a microcode update for Intel CPUs and changes in the Linux kernel. • The history-based attack affects all Intel CPUs with eIBRS, including the latest as of 2025, Intel’s latest generation Lion Cove which features the BHI_NO feature and selected ARM microarchitectures. • Indirect Target Selection (ITS) () affects Intel Core 9th-11th generations and Intel Xeon 2nd-3rd generations. • Lion Cove BPU issue () affects the Lion Cove core, Lunar Lake and Arrow Lake. Also in May 2025, ETH Zurich Computer Security Group "COMSEC" disclosed the
Branch Privilege Injection vulnerability affecting all Intel x86 architectures starting from the 9th generation (Coffee Lake Refresh) under . A microcode update is required to mitigate it. It comes with a performance cost up to 8%. In July 2025, AMD disclosed a new class of speculative execution vulnerabilities known as
Transient Scheduler Attacks (TSA), which were discovered by researchers from Microsoft. The attacks are affecting AMD
Zen 3 and
Zen 4 microarchitectures, and they exploit microarchitectural timing leaks in CPU scheduler logic—specifically, the forwarding of incorrect data during false completion of speculative loads—to infer sensitive data from other processes or privilege levels. TSA encompasses four vulnerabilities: (TSA-SQ), which leaks data from prior stores; (TSA-L1), which leverages the L1 data cache; , enabling speculative reads of control registers; and , which leaks TSC_AUX register values. Mitigations include microcode updates, Linux kernel patches (tsa= tunable), and optional use of the VERW instruction—albeit with potential performance costs. In September 2025, researchers at ETH Zurich disclosed
VMScape (), a
Spectre-BTI-style transient execution attack that exploits incomplete isolation of the branch predictor between guest virtual machines and host user-space hypervisors (notably QEMU under KVM), allowing a malicious guest to influence speculative execution and leak sensitive host memory. The flaw affects
AMD Zen 1–5 and Intel “
Coffee Lake” processors, and mitigations include Linux kernel patches that conditionally issue Indirect Branch Prediction Barrier (IBPB) instructions on VMEXITs before returning control to user-space in order to flush predictor state.
2026 In February 2026 at FOSDEM 2026, the talk "How Secure Are Commercial RISC-V CPUs?" covered the security properties of several commercially available
RISC-V processors and showed that current implementations already exhibit weaknesses related to microarchitectural side channels and speculative behavior. The researchers demonstrated that even relatively "simple"
in-order RISC-V cores can leak sensitive information through timing channels, unprivileged performance counters, and undocumented vendor-specific extensions. The authors argued that manual analysis of such designs does not scale and presented
RISCover, an open-source differential fuzzing framework, to compare architectural behavior across cores and configurations. Using this approach, they identified issues such as out-of-bounds memory accesses and denial-of-service conditions, and suggested that the lack of standardized mechanisms to constrain speculation and timing sources increases the risk of transient execution vulnerabilities similar to those previously observed in x86 and ARM processors. In April 2026, Floating Point Divider State Sampling (FP-DSS), a transient execution vulnerability, affecting multiple generations of AMD CPUs, was reported in a paper titled "TREVEX: A Black-Box Detection Framework For Data-Flow Transient Execution Vulnerabilities". It was assigned . == Future ==