Chromium V8 type confusion (CVE-2025-13223) — handling something made as one type as though it were another

1The shape of type confusion

Data a program handles has a type: a number, a string, a reference to something else. The type settles how a region is read and written. Type confusion is the flaw where a region made as one type is handled as another.

The same sequence of data means different things depending on the type it is read as. Where something placed as a number is read as a reference, whatever that number points to is touched. That is what the catalog points to in naming heap corruption.

2Reachable merely by viewing

1. 1The componentThe JavaScript engine within a browser
2. 2The routeOpening a page runs the processing it contains
3. 3User actionNo special action may be required
4. 4What that meansThe range from which it can be reached is wide

V8 is the part of a browser that runs JavaScript. Open a page and the processing written there runs. Without installing or permitting anything, the everyday act of viewing can bring processing within reach. This site also covers vulnerabilities in devices at a boundary; the difference here is that an individual endpoint is the point reached.

3How many of this class

Of the unpublished records this site holds as of 2026-09-03, 37 are classified as type confusion. Entries for the same engine recur, suggesting that mechanisms performing involved processing at speed are where this class tends to arise.

4That ransomware is not marked

This entry is not marked as known to be used in ransomware campaigns. The catalog, however, lists only what has been confirmed as actually exploited. The absence of that marking does not mean it has not been exploited; it means use in that particular way has not been confirmed. By the time an entry appears in the catalog, the judgment that it was actually used has already been made.