AMD SEV-SNP - RMP entries cached in L1D/L2 leaking physical address bits: Reverse-map table entries cached in L1D and

UnscoredNCVD-2025-004-amd-sev-snp-rmp-entries-cached-iFirmware, BMC & network fabricAMD-SB-3036curated

Impact

Reverse-map table entries cached in L1D and L2 leak up to six physical address bits to an **unprivileged** process. AMD and the researchers agree there is no immediate impact, and six bits is not a compromise on its own - but physical address bits are exactly the primitive that makes Rowhammer, cache-eviction-set construction and DMA targeting practical, so it is a building block for other people's attacks rather than an attack itself.

Who can reach it

Local, unprivileged - notably lower than the rest of the RMP family, which mostly needs hypervisor privilege.

What to do

**No fix planned.** Nothing to install and nothing to reboot for. Treat it as a standing reminder that side-channel primitives accumulate: it lowers the cost of the next attack against your SNP hosts without ever appearing in a patch queue. Track AMD-SB-3036 in case AMD's assessment changes.

References

https://www.amd.com/en/resources/product-security/bulletin/amd-sb-3036.html https://www.amd.com/en/resources/product-security.html

This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.