lib0 `readUint8Array` performs an unbounded read past the end of the decoder’s view, disclosing adjacent process memory

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

A missing bounds check in the binary decoder in lib0, versions 0.2.1-0.2.117 and earlier and 1.0.0-rc.32 and earlier, lets any unauthenticated remote peer read adjacent process memory and receive it back. `readUint8Array` never compares the wire-supplied length against the decoder's own view, so one over-long length prefix returns whatever the host process allocated next: other tenants' document content, personal data, and live bearer session tokens**, recovered in full and at will. An attacker who can supply bytes to a lib0 decoder which means any peer that can open a socket, including before authentication reads adjacent process memory and, where the consumer echoes, stores or re-serves the decoded value, receives it back. This is patched in version 0.2.118 and 1.0.0-rc.33.

Source published

29 Sep 2026 13:11:55 UTC

Source modified

29 Sep 2026 13:55:21 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N