Threadlinqs IntelligenceStart free

Weakness · BaseCWE-367

CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition

Likelihood of exploit: MediumKEV-linkedBase

As of 2026-10-05, CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition) underlies 9 CVEs tracked by Threadlinqs, 2 of them in the CISA Known Exploited Vulnerabilities catalog, and is cited by 36 tracked threats. MITRE rates its likelihood of exploit as Medium.

CVEs
9Mapped to CWE-367
CISA KEV
2Exploited in the wild
Critical
2CVSS v3 critical CVEs
Threats
36Tracked campaigns citing it
Likelihood
MediumMITRE likelihood of exploit

Last updated:

What is CWE-367?

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.

CWE-367 is a base-level weakness in MITRE’s Common Weakness Enumeration, with a MITRE likelihood of exploit of Medium. Applicable platforms: Language: Not Language-Specific.

Source: MITRE CWE (CWE-367 definition, reproduced verbatim). Counts and linkage below are Threadlinqs data.

Consequences

  • Integrity, Other — Alter Execution Logic, Unexpected State. The attacker can gain access to otherwise unauthorized resources.
  • Integrity, Other — Modify Application Data, Modify Files or Directories, Modify Memory, Other. Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
  • Integrity, Other — Other. The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
  • Non-Repudiation — Hide Activities. If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
  • Non-Repudiation, Other — Other. In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
  • Other — Unexpected State. The product may perform invalid actions when the resource is in an unexpected state.

Source: MITRE CWE, common consequences.

How CWE-367 is exploited in the wild

Threadlinqs maps 9 CVEs to CWE-367, published between 2025-03-04 and 2026-10-04. 2 are listed in CISA’s Known Exploited Vulnerabilities catalog, the authoritative record of exploitation in the wild. By CVSS v3 severity the set splits into 2 critical, 4 high, 2 medium. The highest EPSS score in the set is 50.1% (CVE-2025-22224), the modelled probability of exploitation in the next 30 days. 36 tracked threats reference CWE-367 directly or through a CVE it covers; the most recent is “Multiple Vulnerabilities in Microsoft Edge prior to 154.0.4258.53 (HK GovCERT A26-10-03)” (2026-10-02). Affected products concentrate in Microsoft (2), FOSSBilling (1), N8n (1), among 8 vendors in total.

Vulnerabilities (CVEs)

All 9 CVEs mapped to CWE-367, CISA KEV first, then by CVSS score.

Affected vendors

Threat activity

36 tracked threats cite CWE-367; the 25 most recent are listed.

Mitigations

  • Implementation: 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.
  • Implementation: 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.
  • Architecture and Design: Limit the interleaving of operations on files from multiple processes.
  • Implementation, Architecture and Design: If you cannot perform operations atomically and you must share access to the resource between multiple processes or threads, then try to limit the amount of time (CPU cycles) between the check and use of the resource. This will not fix the problem, but it could make it more difficult for an attack to succeed.
  • Implementation: Recheck the resource after the use call to verify that the action was taken appropriately.
  • Architecture and Design: Ensure that some environmental locking mechanism can be used to protect resources effectively.
  • Implementation: Ensure that locking occurs before the check, as opposed to afterwards, such that the resource, as checked, is the same as it is when in use.

Source: MITRE CWE, potential mitigations.

Detection methods (MITRE CWE)

  • Automated Static Analysis (effectiveness: High): Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Source: MITRE CWE, detection methods. Threadlinqs detection rules for the threats above are Blue tier and higher.