Ubuntu Disables Spectre/Meltdown Protections

Security Update News

Update Information

Title Ubuntu Disables Spectre/Meltdown Protections
Update ID SCHNEIER:9BF526CF14AB79F193BA90639A8F3313
Type schneier
Published 2025-07-02T11:02:22
Last Updated 2025-07-01T16:23:54

Security Impact

Severity NONE

AI Analysis

AI Description Ubuntu has disabled Spectre and Meltdown protections, citing a significant performance boost and the difficulty of executing such attacks. This decision follows discussions between Intel and Canonical’s security teams, who agree that the security impact no longer justifies the performance trade-off.
AI Severity Medium
AI Vendor Canonical
AI Product Ubuntu
AI Version various

Update Details

A whole class of speculative execution attacks against CPUs were published in 2018. They seemed pretty catastrophic at the time. But the fixes were as well. Speculative execution was a way to speed up CPUs, and removing those enhancements resulted in significant performance drops.

Now, people are rethinking the trade-off. Ubuntu has disabled some protections, resulting in 20% performance boost.

> After discussion between Intel and Canonical’s security teams, we are in agreement that Spectre no longer needs to be mitigated for the GPU at the Compute Runtime level. At this point, Spectre has been mitigated in the kernel, and a clear warning from the Compute Runtime build serves as a notification for those running modified kernels without those patches. For these reasons, we feel that Spectre mitigations in Compute Runtime no longer offer enough security impact to justify the current performance tradeoff.

I agree with this trade-off. These attacks are hard to get working, and it’s not easy to exfiltrate useful data. There are way easier ways to attack systems.

News article.

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