Local privilege escalation via PPP channel race
Published Aug 10, 2026 · Updated Aug 10, 2026
Use-after-free in the PPP-over-L2TP receive path in Linux allows local users to escalate privileges through a socket-close race. The ppp_release_channel() path frees an internal channel with kfree() without an RCU grace period while pppol2tp_recv() can still pass it to ppp_input(). Local syscall access is sufficient; racing packet reception against socket closure can corrupt kernel memory, disclose it, or crash the host.
Summary
What happened
Use-after-free in the PPP-over-L2TP receive path in Linux allows local users to escalate privileges through a socket-close race. The ppp_release_channel() path frees an internal channel with kfree() without an RCU grace period while pppol2tp_recv() can still pass it to ppp_input(). Local syscall access is sufficient; racing packet reception against socket closure can corrupt kernel memory, disclose it, or crash the host.
The record
- CVE
- CVE-2026-68398
- Published
- Aug 10, 2026
- Updated
- Aug 10, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 10, 2026CVE publishedPublication date reported by the CVE source.
- Aug 10, 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.
- Affected versionversion=26f8819ddd10141ebe7bbce700fbab36bfa5f478
- Affected versionversion=3.16.54 <3.17
- Affected versionversion=3.2.99 <3.3
- Affected versionversion=4.14.182 <4.15
- Affected versionversion=4.15
- Affected versionversion=4.4.225 <4.5
- Affected versionversion=4.9.225 <4.10
- Affected versionversion=5803ecd7f6ac6f747582e775caa62ac9d0489261
- Affected versionversion=9bcc0508576b2d50efd958f2ea1c5906749c2c89
- Affected versionversion=c2984681fe15cfb803a9132aaaf1140ab20a72c1
- Affected versionversion=d36e5ba7bbed5d7bd26e8609ffed503c2def401b
- Affected versionversion=ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 <06213c85d8c0994f786c093b8b2a517987943ca6
- Affected versionversion=ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 <3ab32218d7182705dae5c86f13925f458072da2c
- Affected versionversion=ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 <4bb84e964ff0fe0a171c965362de72f9820dbce9
- Affected versionversion=ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 <c9574b8a8edeb4edd3ac6472c27ef7184bdb2baa
- Affected versionversion=ee40fb2e1eb5bc0ddd3f2f83c6e39a454ef5a741 <ec4215683e47424c9c4762fd3c60f552a3119142
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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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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