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Fencer Vulns
medium 6.5

CVE-2026-85769 json

Libtpms: libtpms: heap out-of-bounds read in tpm2 state unmarshalling via unchecked block_skip_read() blocksize

published 2026-09-04 2 mo ago modified 2026-11-06 3 d ago also EUVD-2026-71627

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

A flaw was found in libtpms, a library that provides software TPM 2.0 emulation. When restoring TPM 2.0 state (for example during a virtual machine's power-on or state/migration restore), a malformed state blob can supply an oversized skip-block length that is not validated against the remaining size of the input buffer. This can drive an internal size counter negative, which bypasses a subsequent bounds check due to an unsafe signed-to-unsigned conversion, causing the parser to read memory outside the bounds of the heap buffer holding the state data. Successful exploitation can crash the process hosting libtpms (such as swtpm), resulting in a denial of service of the emulated TPM device and the virtual machine that depends on it. No data corruption or information disclosure was confirmed.

Patch / fix

  • libtpms SLE Module for Server Applications 15 SP7 0.9.6-150600.3.6.1
  • libtpms Linux Micro 6.0 0.9.6-3.1
  • libtpms Linux Micro 6.1 0.9.6-slfo.1.1_3.1
  • libtpms SLE Micro 5.5, SLE Micro 5.4, SLE Micro 5.3 0.8.2-150300.3.12.1

suse advisories SUSE-SU-2026:4363-1SUSE-SU-2026:23878-1SUSE-SU-2026:23926-1SUSE-SU-2026:4278-1

  • libtpms openSUSE Tumbleweed 0.10.2-2.1

opensuse advisories openSUSE-SU-2026:11836-1

  • libtpms Azure Linux 3.0 0.9.6-9

azure linux advisories AZL-99918

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-85769 updated cvss 6.5

libtpms: libtpms: heap out-of-bounds read in TPM2 state unmarshalling via unchecked block_skip_read() blocksize

  • Red Hat Enterprise Linux 8 libtpms Red Hat Enterprise Linux 9 libtpms, libtpms 0.9.6-11.el10 Red Hat Enterprise Linux 10 libtpms 0.9.6-11.el10
    affected: workaround, no fix available “No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability.”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.