Red Hat Enterprise Linux 2.0 libtpms signed conversion

Summaryinfo

A vulnerability was found in Red Hat Enterprise Linux 2.0. It has been rated as critical. This impacts an unknown function of the component libtpms. This manipulation causes signed conversion. This vulnerability appears as CVE-2026-85769. The attack requires local access. There is no available exploit.

Detailsinfo

A vulnerability classified as critical was found in Red Hat Enterprise Linux 2.0. Affected by this vulnerability is an unknown function of the component libtpms. The manipulation with an unknown input leads to a signed conversion vulnerability. The CWE definition for the vulnerability is CWE-195. The product uses a signed primitive and performs a cast to an unsigned primitive, which can produce an unexpected value if the value of the signed primitive can not be represented using an unsigned primitive. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at access.redhat.com. This vulnerability is known as CVE-2026-85769 since 09/04/2026. The exploitation appears to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/04/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Operating System

Vendor

• Red Hat

Name

• Enterprise Linux

Version

• 2.0

License

• commercial

Website

• Vendor: https://www.redhat.com/

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