Invalid kernel read via stale conntrack pointer
Published Jul 29, 2024 · Updated Aug 5, 2026
Use-after-free in Linux kernel net/sched act_ct allows local users to trigger an invalid kernel-memory read during a conntrack clash. After __nf_conntrack_confirm resolves a clash and drops ct, tcf_ct_act passes that stale pointer to tcf_ct_flow_table_process_conn instead of retrieving ct from the packet again. Local access and an active act_ct traffic-control path are required; KASAN observed a one-byte use-after-free read in interrupt context.
Summary
What happened
Use-after-free in Linux kernel net/sched act_ct allows local users to trigger an invalid kernel-memory read during a conntrack clash. After __nf_conntrack_confirm resolves a clash and drops ct, tcf_ct_act passes that stale pointer to tcf_ct_flow_table_process_conn instead of retrieving ct from the packet again. Local access and an active act_ct traffic-control path are required; KASAN observed a one-byte use-after-free read in interrupt context.
The record
- CVE
- CVE-2024-41040
- Published
- Jul 29, 2024
- Updated
- Aug 5, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-416
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 29, 2024CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=0cc254e5aa37cf05f65bcdcdc0ac5c58010feb33 <26488172b0292bed837b95a006a3f3431d1898c3
- Affected versionversion=0cc254e5aa37cf05f65bcdcdc0ac5c58010feb33 <2b4d68df3f57ea746c430941ba9c03d7d8b5a23f
- Affected versionversion=0cc254e5aa37cf05f65bcdcdc0ac5c58010feb33 <4e71b10a100861fb27d9c5755dfd68f615629fae
- Affected versionversion=0cc254e5aa37cf05f65bcdcdc0ac5c58010feb33 <799a34901b634008db4a7ece3900e2b971d4c932
- Affected versionversion=0cc254e5aa37cf05f65bcdcdc0ac5c58010feb33 <ef472cc6693b16b202a916482df72f35d94bd69e
- Affected versionversion=30822781c89943b6a3ed122324ceb37cea7042a3
- Affected versionversion=5.10.43 <5.10.222
- Affected versionversion=5.12.10 <5.13
- Affected versionversion=5.13
- Affected versionversion=f07c548314776231f0d47d73ec6caa5b17e876e8 <b81a523d54ea689414f67c9fb81a5b917a41ed55
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Published CVSS scores
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Attacks
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