Kernel memory exposure and crash via key mismatch
Published Mar 6, 2025 · Updated Aug 5, 2026
Improper input validation in Linux nf_tables allows local users to disclose kernel memory or crash the system via malformed pipapo sets. pipapo_init rounds each concatenated field to 32 bits, but nf_tables accepts a field-length sum that differs from the aligned set key length, causing out-of-bounds reads and corrupted lookup state. Exploitation requires local nfnetlink access with CAP_NET_ADMIN, which an unprivileged user namespace can supply; exposed data can be inferred from match results, while hardened systems can panic.
Summary
What happened
Improper input validation in Linux nf_tables allows local users to disclose kernel memory or crash the system via malformed pipapo sets. pipapo_init rounds each concatenated field to 32 bits, but nf_tables accepts a field-length sum that differs from the aligned set key length, causing out-of-bounds reads and corrupted lookup state. Exploitation requires local nfnetlink access with CAP_NET_ADMIN, which an unprivileged user namespace can supply; exposed data can be inferred from match results, while hardened systems can panic.
The record
- CVE
- CVE-2025-21826
- Published
- Mar 6, 2025
- Updated
- Aug 5, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-20, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 6, 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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Your stack
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