CVE-2026-53162

Description

In the Linux kernel, the following vulnerability has been resolved: memcg: use round-robin victim selection in refill_stock Harry Yoo reported that get_random_u32_below() is not safe to call in the nmi context and memcg charge draining can happen in nmi context. More specifically get_random_u32_below() is neither reentrant- nor NMI-safe: it acquires a per-cpu local_lock via local_lock_irqsave() on the batched_entropy_u32 state. An NMI that lands on a CPU mid-update of the ChaCha batch state and recurses into the random subsystem would corrupt that state. The memcg_stock local_trylock prevents re-entry on the percpu stock itself, but cannot protect an unrelated subsystem's per-cpu lock. Replace the random pick with a per-cpu round-robin counter stored in memcg_stock_pcp and serialized by the same local_trylock that already guards cached[] and nr_pages[]. No atomics, no random calls, no extra locks needed.

CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/00731bd7e18f182a32ca54d6b176eaa470b51ed7 https://git.kernel.org/stable/c/89bd8215e25aa6999cc51696da418e0d422bc5e0 https://git.kernel.org/stable/c/c0cafe24d3f6534294c4b2bc2d47734ff7cbd313

Frequently Asked Questions

What is CVE-2026-53162? +

In the Linux kernel, the following vulnerability has been resolved: memcg: use round-robin victim selection in refill_stock Harry Yoo reported that get_random_u32_below() is not safe to call in the nmi context and memcg charge draining can happen in nmi context. More specifically get_random_u32_below() is neither reentrant- nor NMI-safe: it acquires a per-cpu local_lock via local_lock_irqsave() on the batched_entropy_u32 state. An NMI that lands on a CPU mid-update of the ChaCha batch state and recurses into the random subsystem would corrupt that state. The memcg_stock local_trylock prevents re-entry on the percpu stock itself, but cannot protect an unrelated subsystem's per-cpu lock. Replace the random pick with a per-cpu round-robin counter stored in memcg_stock_pcp and serialized by the same local_trylock that already guards cached[] and nr_pages[]. No atomics, no random calls, no extra locks needed. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-53162? +

CVE-2026-53162 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53162? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.