AMD Zen 1 through Zen 4 Safe RET Interrupt security flaw
Vulnerability
Summary
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Safe RET Interrupt Vulnerability affects Zen 1 through Zen 4 processors, where a local attacker can time an interrupt injection to weaken Safe RET and expose kernel memory. Researchers from MIT CSAIL described the attack on February 5 after showing a Linux timing window between branch-predictor sanitization and kernel use. On August 6, AMD issued AMD-SB-7061 and said the issue appears tied to the Linux implementation of Safe RET, with potential information disclosure on affected systems.
Related Happenings
INTERRUPT INJECTION TONTOU analysis bypassing Spectre v2 defenses on Linux
Technical Analysis
H score24
First: 06.08.2026 19:17
Last: 06.08.2026 19:17
Sources 1
How related:
The researchers developed an Interrupt Injection attack, where “unprivileged user programs can schedule timer interrupts to occur during kernel execution.”
About this happening:
MIT CSAIL researchers disclosed INTERRUPT INJECTION, a TONTOU timing primitive that can bypass Spectre v2 defenses on Linux by using unprivileged code to s...
INTERRUPT INJECTION TONTOU analysis bypassing Spectre v2 defenses on Linux
Technical AnalysisHow related: The researchers developed an Interrupt Injection attack, where “unprivileged user programs can schedule timer interrupts to occur during kernel execution.”
About this happening: MIT CSAIL researchers disclosed INTERRUPT INJECTION, a TONTOU timing primitive that can bypass Spectre v2 defenses on Linux by using unprivileged code to s...
Timeline
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06.08.2026 19:17 1 articles · 2h ago
Researchers disclose INTERRUPT INJECTION to AMD and Intel
Initial DisclosureMIT CSAIL researchers Daniël Trujillo and Mengjia Yan notified AMD and Intel about INTERRUPT INJECTION on February 5, after developing a Linux timing attack that can time a hardware interrupt to land between branch-predictor sanitization and kernel use.
Show sources
- New Interrupt Injection Attack Can Bypass Spectre v2 Defenses on Intel and AMD CPUs — thehackernews.com — 06.08.2026 19:17
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06.08.2026 19:17 3 articles · 2h ago
AMD publishes Safe RET Interrupt Vulnerability bulletin
Mitigation Patch UpdateOn August 6, AMD issued AMD-SB-7061 for Safe RET Interrupt Vulnerability, naming Zen 1 through Zen 4 processors as affected and saying an attacker on an affected system could inject an interrupt at a precise moment to disrupt Safe RET, weaken that protection, and potentially cause information disclosure; MIT says a kernel patch has since shipped in a normal operating-system update.
Show sources
- New Interrupt Injection Attack Can Bypass Spectre v2 Defenses on Intel and AMD CPUs — thehackernews.com — 06.08.2026 19:17
- New Interrupt Injection Attack Can Bypass Spectre v2 Defenses on Intel and AMD CPUs — thehackernews.com — 06.08.2026 19:17
- New TONTOU CPU attack bypasses Spectre v2 fixes, leaks Linux password hashes — www.bleepingcomputer.com — 06.08.2026 21:03