jackson-core: UTF8DataInputJsonParser._reportInvalidToken() missing maxErrorTokenLength limit -> unbounded StringBuilder growth (DoS)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-89425: 0.53% estimated exploitation activity in the next 30 days; percentile 45.03 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Status FULLY REPRODUCED. A malformed token fed through createParser(DataInput) produced a 20,000,109-character exception message from a 20-million-character attacker payload, while the identical payload fed through createParser(InputStream) produced a correctly bounded 367-character message. Affected Component / Version - Package: com.fasterxml.jackson.core:jackson-core - Confirmed against: jackson-core-2.20.2 - Affected file: src/main/java/com/fasterxml/jackson/core/json/UTF8DataInputJsonParser.java (reportInvalidToken(int, String, String), lines ~2763-2780 in the 2.20.2 tree) Technical Analysis UTF8DataInputJsonParser.reportInvalidToken() builds the offending-token description for its exception message by appending identifier characters one at a time to a bare StringBuilder: There is no check against ErrorReportConfiguration.getMaxErrorTokenLength() (default 256) anywhere in this loop. By contrast, the sibling UTF8StreamJsonParser implementation of the same logic does enforce it:…

Published by the source

1 Oct 2026, 15:20 UTC

Last modified by the source

1 Oct 2026, 15:30 UTC

Source last checked

26 Oct 2026, 16:56 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7hhh-6rmp-j9qf

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7hhh-6rmp-j9qf

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# Patch Next advisory brief: CVE-2026-89425

Advisory: jackson-core: UTF8DataInputJsonParser._reportInvalidToken() missing maxErrorTokenLength limit -> unbounded StringBuilder growth (DoS)
IDs: CVE-2026-89425, GHSA-7hhh-6rmp-j9qf
Record: https://patchnext.com/advisories/cve-2026-89425 (revision 2, source checked 26 Oct 2026, 16:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: com.fasterxml.jackson.core:jackson-core 2.22.3, 2.21.7, 2.18.11; tools.jackson.core:jackson-core 3.2.3, 3.1.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven com.fasterxml.jackson.core:jackson-core: affected >= 2.19.0, <= 2.21.6; >= 2.22.0, <= 2.22.2; >= 2.8.0, <= 2.18.10; fixed in 2.18.11, 2.22.3, 2.21.7
- Maven tools.jackson.core:jackson-core: affected >= 3.0.0, <= 3.1.6; >= 3.2.0, <= 3.2.2; fixed in 3.2.3, 3.1.7

## Suggested inspection (read-only)
- Maven com.fasterxml.jackson.core:jackson-core: check the installed version with your package manager.
- Maven tools.jackson.core:jackson-core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on com.fasterxml.jackson.core:jackson-core, tools.jackson.core:jackson-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-7hhh-6rmp-j9qf (OSV record GHSA-7hhh-6rmp-j9qf lists affected ranges: Maven com.fasterxml.jackson.core:jackson-core >=2.19.0 =2.22.0 =2.8.0 =3.0.0 =3.2.0 <3.2.3 (fixed))
- Verified: https://github.com/advisories/GHSA-7hhh-6rmp-j9qf (GitHub-reviewed advisory GHSA-7hhh-6rmp-j9qf lists affected ranges: Maven com.fasterxml.jackson.core:jackson-core >=2.19.0 =2.22.0 =2.8.0 =3.0.0 =3.2.0 <=3.2.2)

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