ra-tls-clients: Time-of-check Time-of-use (TOCTOU) Race Condition
CVE-2026-108361 is a high-severity time-of-check time-of-use (TOCTOU) race condition vulnerability in ra-tls-clients from Privasys, with a CVSS 4.0 base score of 7.2 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. Affected ra-tls-clients versions: < 0.9.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.08% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of ra-tls-clients you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Privasys | ra-tls-clients | < 0.9.1 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- NoneNo loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (github.com).
Official description
Privasys Remote Attestation TLS Clients provides multi-language utilities for verifying attested TLS connections. Before 0.9.1, an attacker with local access could modify workload code, data, and configuration at any time after successful connection establishment. Once Evidence was successfully appraised and the connection was established, there was a window of vulnerability from the establishment of the connection to the termination of the connection where an attacker could modify the state of the workload and platform at runtime on the TLS endpoint acting as the Attester. This vulnerability was possible because Privasys/ra-tls-clients performed attestation only once in the lifetime of the connection (at connection establishment time), and the verifying peer continued to believe that the state was the same as in the initial Evidence throughout, whereas it could be stale at some point in time. This vulnerability is fixed in 0.9.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Time-of-check Time-of-use (TOCTOU) Race Condition
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
How developers prevent this class of flaw
- The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
- When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
- Limit the interleaving of operations on files from multiple processes.
More Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities (CWE-367)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in ra-tls-clients
- 9.1 Critical severity
- 9.1 Critical severity
Recent Time-of-check Time-of-use (TOCTOU) Race Condition vulnerabilities
- 8.1 High severity
- 8.1 High severity
- 7.3 High severity
- 8.3 High severity
- 8.8 High severity
- 7.8 High severity
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