System crash via jbd2 assertion on corrupted filesystem
Published Dec 22, 2025 · Updated Dec 22, 2025
Denial of service in Linux jbd2 allows attackers to crash the system through operations on an inconsistent ext4 file system. In jbd2_journal_get_create_access(), reused blocks caused by inconsistent bitmap data violate an assumed invariant, and J_ASSERT invokes BUG_ON instead of aborting the journal. Triggering it requires errors=continue mode with storage failures and inconsistent metadata, or a deliberately constructed image and specific operations.
Summary
What happened
Denial of service in Linux jbd2 allows attackers to crash the system through operations on an inconsistent ext4 file system. In jbd2_journal_get_create_access(), reused blocks caused by inconsistent bitmap data violate an assumed invariant, and J_ASSERT invokes BUG_ON instead of aborting the journal. Triggering it requires errors=continue mode with storage failures and inconsistent metadata, or a deliberately constructed image and specific operations.
The record
- CVE
- CVE-2025-68337
- Published
- Dec 22, 2025
- Updated
- Dec 22, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Dec 22, 2025CVE publishedPublication date reported by the CVE source.
- Dec 22, 2025Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=2.6.19
- Affected versionversion=470decc613ab2048b619a01028072d932d9086ee <986835bf4d11032bba4ab8414d18fce038c61bb4
- Affected versionversion=470decc613ab2048b619a01028072d932d9086ee <a2a7f854d154a3e9232fec80782dad951655f52f
- Affected versionversion=470decc613ab2048b619a01028072d932d9086ee <aa1703f3f706ea0867fb1991dcac709c9ec94cfb
- Affected versionversion=470decc613ab2048b619a01028072d932d9086ee <bf34c72337e40c4670cceeb79b353356933a254b
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What is affected?
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Attacks
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Technologies
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