CVE-2026-104895
jackson-dataformat-smile: unbounded eager byte[] allocation for raw binary in the async parser allows OutOfMemoryError denial of service
Description
The asynchronous Smile parser (NonBlockingByteArrayParser) uses a raw-binary length prefix taken from untrusted input to allocate a byte[] before the body is read, with no upper bound and no overflow check. On the raw-binary marker 0xFD, _decodeVInt() computes (value << 6) + (i & 0x3F) without the (value >>> 25) != 0 overflow guard present in the blocking SmileParser._readUnsignedVInt, and _startRawBinary then allocates the declared length immediately. A Smile feed of roughly ten bytes can therefore force an eager allocation of approximately 2 GB, producing an OutOfMemoryError on reactive or asynchronous Smile endpoints. A VInt crafted to overflow int yields a negative length and a NegativeArraySizeException, a RuntimeException that is not a JacksonException and so escapes the parser contract. Either outcome crashes the request or processing thread. This is the same class of issue as CVE-2020-28491 in the CBOR parser of this library, which was fixed with a LONGEST_NON_CHUNKED_BINARY guard; the asynchronous Smile parser never received the equivalent guard. No privileges or user interaction beyond the ability to submit data for parsing are required.
INFO
Published Date :
Oct. 28, 2026, 12:17 a.m.
Last Modified :
Oct. 28, 2026, 12:17 a.m.
Remotely Exploit :
Yes !
Source :
36c7be3b-2937-45df-85ea-ca7133ea542c
Affected Products
The following products are affected by CVE-2026-104895
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 36c7be3b-2937-45df-85ea-ca7133ea542c |
Solution
- Apply the fix for CVE-2020-28491 to the asynchronous Smile parser.
- Implement an upper bound for buffer allocation.
- Add overflow checks for length calculations.
- Validate the calculated length before allocation.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-104895.
| URL | Resource |
|---|---|
| https://github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA-h3c2-2m49-r49w |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-104895 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-104895
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-104895 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-104895 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 36c7be3b-2937-45df-85ea-ca7133ea542c
Oct. 28, 2026
Action Type Old Value New Value Added Description The asynchronous Smile parser (NonBlockingByteArrayParser) uses a raw-binary length prefix taken from untrusted input to allocate a byte[] before the body is read, with no upper bound and no overflow check. On the raw-binary marker 0xFD, _decodeVInt() computes (value << 6) + (i & 0x3F) without the (value >>> 25) != 0 overflow guard present in the blocking SmileParser._readUnsignedVInt, and _startRawBinary then allocates the declared length immediately. A Smile feed of roughly ten bytes can therefore force an eager allocation of approximately 2 GB, producing an OutOfMemoryError on reactive or asynchronous Smile endpoints. A VInt crafted to overflow int yields a negative length and a NegativeArraySizeException, a RuntimeException that is not a JacksonException and so escapes the parser contract. Either outcome crashes the request or processing thread. This is the same class of issue as CVE-2020-28491 in the CBOR parser of this library, which was fixed with a LONGEST_NON_CHUNKED_BINARY guard; the asynchronous Smile parser never received the equivalent guard. No privileges or user interaction beyond the ability to submit data for parsing are required. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-789 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/104xxx/CVE-2026-104895.json">CVE-2026-104895</a> Added Reference https://github.com/FasterXML/jackson-dataformats-binary/security/advisories/GHSA-h3c2-2m49-r49w