FasterXML jackson-dataformat-smile Asynchronous Smile Parser _decodeVInt allocation of resources

Summaryinfo

A vulnerability has been found in FasterXML jackson-dataformat-smile and classified as problematic. Affected by this vulnerability is the function _decodeVInt of the component Asynchronous Smile Parser. Performing a manipulation results in allocation of resources. This vulnerability is reported as CVE-2026-104895. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, was found in FasterXML jackson-dataformat-smile (the affected version unknown). This affects the function _decodeVInt of the component Asynchronous Smile Parser. The manipulation with an unknown input leads to a allocation of resources vulnerability. CWE is classifying the issue as CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. This is going to have an impact on availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-104895 since 10/02/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-111530). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Programming Language Software

Vendor

• FasterXML

Name

• jackson-dataformat-smile

License

• open-source

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CPE 2.2info

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Be aware that VulDB is the high quality source for vulnerability data.

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