CVE-2022-49637

Local availability failure via unsynchronized FIB threshold read

Published Feb 26, 2025 · Updated May 11, 2026

Race condition in the IPv4 FIB trie in Linux 5.2 through 5.18.12 allows local users to cause an unspecified availability failure. The tnode_free function compares accumulated freed-trie memory with sysctl_fib_sync_mem while that writable threshold can change concurrently, so the read is not atomic. Low-privilege local access and precise timing are required; public sources do not specify whether the resulting failure is a hang, crash, or another interruption.

CVSS severity4.7
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the IPv4 FIB trie in Linux 5.2 through 5.18.12 allows local users to cause an unspecified availability failure. The tnode_free function compares accumulated freed-trie memory with sysctl_fib_sync_mem while that writable threshold can change concurrently, so the read is not atomic. Low-privilege local access and precise timing are required; public sources do not specify whether the resulting failure is a hang, crash, or another interruption.

The record

CVE
CVE-2022-49637
Published
Feb 26, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 26, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.2
  2. Affected versionversion=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <190cd4ff128373271e065afb20f1d2247b3f10c3
  3. Affected versionversion=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <418b191d5f223a8cb6cab09eae1f72c04ba6adf2
  4. Affected versionversion=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <73318c4b7dbd0e781aaababff17376b2894745c0
  5. Affected versionversion=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <7c1acd98fb221dc0d847451b9ab86319f8b9916c
  6. Affected versionversion=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <9be8aac91960ea32fd0e874758c9afee665c57d2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.2; version=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <190cd4ff128373271e065afb20f1d2247b3f10c3; version=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <418b191d5f223a8cb6cab09eae1f72c04ba6adf2; version=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <73318c4b7dbd0e781aaababff17376b2894745c0; version=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <7c1acd98fb221dc0d847451b9ab86319f8b9916c; version=9ab948a91b2c2abc8e82845c0e61f4b1683e3a4f <9be8aac91960ea32fd0e874758c9afee665c57d2

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7CISA-ADPCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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