CVE-2026-89425jackson-core: UTF8DataInputJsonParser._reportInvalidToken() does not honor maxErrorTokenLength, allowing unbounded StringBuilder growth
- 7.5HighCVSS base score
- 0.61%Exploitation in 30 daysEPSS · top 50% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
UTF8DataInputJsonParser._reportInvalidToken() in FasterXML jackson-core builds the offending-token text for its error message by appending Java identifier characters to a StringBuilder in a loop that has no upper bound. Unlike the three sibling parser implementations, including UTF8StreamJsonParser, it never consults ErrorReportConfiguration.getMaxErrorTokenLength() (default 256). A malformed token supplied to a parser created through JsonFactory.createParser(DataInput) is therefore accumulated in full. No StreamReadConstraints setting mitigates this: maxDocumentLength cannot be applied to DataInput sources at all, and maxStringLength does not cover this path because the accumulation bypasses ReadConstrainedTextBuffer. The reporter measured a 20,000,109-character exception message from a 20-million-character malformed token on the DataInput path, against 367 characters for identical input on the InputStream path. Scaling the payload drives the StringBuilder, which also incurs byte-to-char expansion and internal array doubling, to many times the raw payload size and can trigger OutOfMemoryError for the whole JVM. UTF8DataInputJsonParser was introduced in 2.8.0 together with createParser(DataInput); releases before 2.8.0 do not contain the affected class.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- GHSA-7hhh-6rmp-j9qf (opens in a new tab)vendor-advisoryexploit
Timeline
ID reserved
By HeroDevs
- 12 days later
· 12 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| HeroDevsCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Deferred | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.61% · top 50% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- affected 2.8.0 – ≤ 2.18.10
- affected 2.19.0 – ≤ 2.21.6
- affected 2.22.0 – ≤ 2.22.2
- affected 3.0.0 – ≤ 3.1.6
- affected 3.2.0 – ≤ 3.2.2
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavencom.fasterxml.jackson.core:jackson-coreGHSA-7hhh-6rmp-j9qf (opens in a new tab)
- Maventools.jackson.core:jackson-coreGHSA-7hhh-6rmp-j9qf (opens in a new tab)
What to do
Solution: Upgrade to com.fasterxml.jackson.core:jackson-core 2.18.11, 2.21.7 or 2.22.3, or to tools.jackson.core:jackson-core 3.1.7 or 3.2.3. The 2.8.x through 2.17.x, 2.19.x, 2.20.x and 3.0.x lines received no fix on their own branch and are no longer maintained upstream; consumers of those lines must move forward to a maintained release.
Workaround: No StreamReadConstraints or ErrorReportConfiguration setting mitigates this issue on the affected code path. Where possible, avoid JsonFactory.createParser(DataInput) for attacker-supplied content and use createParser(InputStream), createParser(Reader) or a byte-array overload instead; those parser implementations enforce maxErrorTokenLength correctly. Otherwise, bound input size ahead of the parser and cap JVM heap so that a single request cannot exhaust process memory.
References
References2
- GHSA-7hhh-6rmp-j9qf (opens in a new tab)vendor-advisoryexploit
- FasterXML/jackson-core#1698 (opens in a new tab)patch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-85000 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-7hhh-6rmp-j9qf (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-89425)Record last updated .