$ cve CVE-2021-42114 JSON

CVE-2021-42114

9.0

CRITICAL · CVSS 3.1 · EPSS 3% (pctl 87)

In your normal cycle

Critical by CVSS (9), but no sign of active exploitation.

Description

Modern DRAM devices (PC-DDR4, LPDDR4X) are affected by a vulnerability in their internal Target Row Refresh (TRR) mitigation against Rowhammer attacks. Novel non-uniform Rowhammer access patterns, consisting of aggressors with different frequencies, phases, and amplitudes allow triggering bit flips on affected memory modules using our Blacksmith fuzzer. The patterns generated by Blacksmith were able to trigger bitflips on all 40 PC-DDR4 DRAM devices in our test pool, which cover the three major DRAM manufacturers: Samsung, SK Hynix, and Micron. This means that, even when chips advertised as Rowhammer-free are used, attackers may still be able to exploit Rowhammer. For example, this enables privilege-escalation attacks against the kernel or binaries such as the sudo binary, and also triggering bit flips in RSA-2048 keys (e.g., SSH keys) to gain cross-tenant virtual-machine access. We can confirm that DRAM devices acquired in July 2020 with DRAM chips from all three major DRAM vendors (Samsung, SK Hynix, Micron) are affected by this vulnerability. For more details, please refer to our publication.

Scoring

CVSS	9.0 (CRITICAL, v3.1)
Vector	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS	2.98% — more likely to be exploited than 87% of all CVEs
Weakness	CWE-20
On CISA KEV	no
Public exploit	none known
Published	2021-11-16
Last modified	2026-06-17

Affected (12)

Vendor	Product
micron	ddr4 sdram
micron	ddr4 sdram firmware
micron	lddr4
micron	lddr4 firmware
samsung	ddr4 sdram
samsung	ddr4 sdram firmware
samsung	lddr4
samsung	lddr4 firmware
skhynix	ddr4 sdram
skhynix	ddr4 sdram firmware
skhynix	lddr4
skhynix	lddr4 firmware

References

→ the Explorer · watch your stack · NVD