Kernel memory disclosure and crash via counter underflow
Published Jan 19, 2025 · Updated Aug 5, 2026
Out-of-bounds read in Linux sch_cake allows local users to disclose kernel memory or crash the system through crafted CAKE traffic. In net/sched/sch_cake.c, inconsistent decrement logic underflows a per-host bulk-flow counter and indexes quantum_div beyond its 1,025 entries. A local user can create a network namespace, attach CAKE through rtnetlink, and drive crafted packet flows; the default triple-isolate mode is exposed.
Summary
What happened
Out-of-bounds read in Linux sch_cake allows local users to disclose kernel memory or crash the system through crafted CAKE traffic. In net/sched/sch_cake.c, inconsistent decrement logic underflows a per-host bulk-flow counter and indexes quantum_div beyond its 1,025 entries. A local user can create a network namespace, attach CAKE through rtnetlink, and drive crafted packet flows; the default triple-isolate mode is exposed.
The record
- CVE
- CVE-2025-21647
- Published
- Jan 19, 2025
- Updated
- Aug 5, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-125
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 19, 2025CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=0 <*
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Published CVSS scores
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Attacks
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Technologies
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