ProtobufParser parses length-prefixed protobuf string and bytes fields by checking (inputPtr + len) <= inputEnd and then, on the fast path,…
CVE-2026-104016
ProtobufParser parses length-prefixed protobuf string and bytes fields by checking (inputPtr + len) <= inputEnd and then, on the fast path, calling finishShortText(len). Both use 32-bit signed integer arithmetic. When an attacker supplies a varint decoding to a length near Integer.MAXVALUE, inputPtr + len overflows to a negative value, the bounds check passes, and finishShortText(len) reaches TextBuffer.expandCurrentSegment(len), which performs Arrays.copyOf with no cap and throws OutOfMemoryError: Requested array size exceeds VM limit. The JVM refuses arrays larger than Integer.MAXVALUE - 8 before consulting available heap, so -Xmx tuning does not mitigate the issue. StreamReadConstraints.maxStringLength and maxDocumentLength do not gate this path: a 33-byte payload is far below any document-length cap and the string-length check does not fire before the allocation. This was confirmed empirically against shipping artifacts with maxStringLength, maxDocumentLength and maxNestingDepth all configured. A February 2026 hardening commit added the equivalent overflow guard to the packed-array-length and message-length paths but left the string-length call sites unguarded. No privileges…
Assessment
- CVSS
- 7.5 (v3.1)
- Severity
- High
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 28 October 2026
- Last updated
- 28 October 2026
- Weakness
- CWE-190
- Assigner
- 36c7be3b-2937-45df-85ea-ca7133ea542c
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
At the source
References
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