Service interruption via conntrack reference leak
Published Feb 26, 2025 · Updated Jun 1, 2026
A reference leak in the Linux kernel act_ct action allows local users to exhaust memory by switching conntrack zones or namespaces. When cached conntrack state cannot be reused, tcf_ct_skb_nfct_cached() returns false and tcf_ct_flow_table_lookup() overwrites the old entry without releasing its reference. Low-privileged local access plus traffic-control use is required; repeated transitions can deplete kernel memory and interrupt service.
Summary
What happened
A reference leak in the Linux kernel act_ct action allows local users to exhaust memory by switching conntrack zones or namespaces. When cached conntrack state cannot be reused, tcf_ct_skb_nfct_cached() returns false and tcf_ct_flow_table_lookup() overwrites the old entry without releasing its reference. Low-privileged local access plus traffic-control use is required; repeated transitions can deplete kernel memory and interrupt service.
The record
- CVE
- CVE-2022-49183
- Published
- Feb 26, 2025
- Updated
- Jun 1, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 26, 2025CVE publishedPublication date reported by the CVE source.
- Jun 1, 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?
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- Affected versionversion=0fc1847359964e95e521cf2bb2b10f8e33dd0970 <9222a08be539cbb7a8e0d46cbc7ab9e4db273eb8
- Affected versionversion=2f131de361f6d0eaff17db26efdb844c178432f8 <b24793a37d91aacad7cb9893b226a7924a89636a
- Affected versionversion=2f131de361f6d0eaff17db26efdb844c178432f8 <bcb74e132a76ce0502bb33d5b65533a4ed72d159
- Affected versionversion=5.10.103 <5.10.258
- Affected versionversion=5.15.26 <5.15.33
- Affected versionversion=5.16.12 <5.16.19
- Affected versionversion=5.17
- Affected versionversion=a95ea90deb3071c1ded77a05e91cfebc5238d908 <bcbf4e5c3b5b373cd61528392dd1ec8e9c0fd33d
- Affected versionversion=e9408de00e5ecd0dbe91cf061c7da23711c4febb <4bb42d73def9411e5cad885b9811987d72431df1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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