CVE-2022-49698

Status: AnalyzedHigh (7.8)—

In the Linux kernel, the following vulnerability has been resolved:

netfilter: use get_random_u32 instead of prandom

bh might occur while updating per-cpu rnd_state from user context, ie. local_out path.

Use the random driver instead, this also avoids need for local prandom state. Moreover, prandom now uses the random driver since d4150779e60f ("random32: use real rng for non-deterministic randomness").

Based on earlier patch from Pablo Neira.

Technical details traces, logs and code from the original report

BUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725
caller is nft_ng_random_eval+0x24/0x54 [nft_numgen]
Call Trace:
 check_preemption_disabled+0xde/0xe0
 nft_ng_random_eval+0x24/0x54 [nft_numgen]

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Base score: 7.8

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.30%
Percentile among all scored CVEs: 20
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1068 Exploitation for Privilege Escalationprivilege escalation85 %
Primary impactT1059 Command and Scripting Interpreterexecution75 %

Vulnerabilidad local (AV:L, PR:L) en kernel Linux que permite ejecución de código con privilegios elevados mediante manipulación del estado rnd_state en netfilter, causando escalada de privilegios.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Execution Prevention Threat Intelligence Program Restrict Web-Based Content Privileged Account Management Limit Software Installation Behavior Prevention on Endpoint

Affected technologies (1)

Linux — Linux Kernel

CWEs

NVD-CWE-noinfo

References

Raw JSON (NVD)

Show

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      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: use get_random_u32 instead of prandom\n\nbh might occur while updating per-cpu rnd_state from user context,\nie. local_out path.\n\nBUG: using smp_processor_id() in preemptible [00000000] code: nginx/2725\ncaller is nft_ng_random_eval+0x24/0x54 [nft_numgen]\nCall Trace:\n check_preemption_disabled+0xde/0xe0\n nft_ng_random_eval+0x24/0x54 [nft_numgen]\n\nUse the random driver instead, this also avoids need for local prandom\nstate. Moreover, prandom now uses the random driver since d4150779e60f\n(\"random32: use real rng for non-deterministic randomness\").\n\nBased on earlier patch from Pablo Neira."
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      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: el uso de get_random_u32 en lugar de prandom bh podría ocurrir mientras se actualiza rnd_state por CPU desde el contexto del usuario, es decir, la ruta local_out. ERROR: uso de smp_processor_id() en código preemptible [00000000]: el llamador de nginx/2725 es nft_ng_random_eval+0x24/0x54 [nft_numgen] Rastreo de llamadas: check_preemption_disabled+0xde/0xe0 nft_ng_random_eval+0x24/0x54 [nft_numgen] Use el controlador aleatorio en su lugar, esto también evita la necesidad de un estado prandom local. Además, prandom ahora usa el controlador aleatorio desde d4150779e60f (\"random32: use real rng for non-deterministic randomness\"). Basado en un parche anterior de Pablo Neira."
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  "lastModified": "2026-06-17T05:18:53.813",
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