Virtual machine crash via unchecked state length
Published Sep 4, 2026 · Updated Sep 4, 2026
Heap out-of-bounds read in libtpms on Red Hat Enterprise Linux 8, 9, and 10 allows attackers to crash a TPM-dependent virtual machine. During TPM 2.0 state restoration, block_skip_read accepts a skip-block length larger than the remaining input, drives a signed size counter negative, and converts it to an unsigned value that bypasses a later bounds check. Exploitation requires control of a state blob consumed at power-on or migration restore; the resulting read can crash the libtpms host process and interrupt the emulated TPM and dependent virtual machine, with no confirmed disclosure or corruption.
Summary
What happened
Heap out-of-bounds read in libtpms on Red Hat Enterprise Linux 8, 9, and 10 allows attackers to crash a TPM-dependent virtual machine. During TPM 2.0 state restoration, block_skip_read accepts a skip-block length larger than the remaining input, drives a signed size counter negative, and converts it to an unsigned value that bypasses a later bounds check. Exploitation requires control of a state blob consumed at power-on or migration restore; the resulting read can crash the libtpms host process and interrupt the emulated TPM and dependent virtual machine, with no confirmed disclosure or corruption.
The record
- CVE
- CVE-2026-85769
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- T1499
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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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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