jackson-core: Async parser maxNumberLength bypass via chunked digit accumulation (incomplete fix for GHSA-72hv-8253-57qq)

Exploitation

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

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-68494: 0.46% estimated exploitation activity in the next 30 days; percentile 40.20 (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.

Summary The fix released in jackson-core 2.18.6 and 2.21.1 for GHSA-72hv-8253-57qq (Number Length Constraint Bypass in Async Parser, published 2026-02-28) is incomplete. The fix commit b0c428e6 (#1555) wired validateIntegerLength into a new setIntLength helper and called it at every place where the integer portion of a number is decided (terminator byte arrived, . / e/E seen, end-of-feed inside a fully-buffered value). It did not call it on the much more attacker-relevant path: "ran out of input while still inside MINORNUMBERINTEGERDIGITS, return NOTAVAILABLE to caller". As a result, an attacker who streams JSON to a non-blocking parser in many small chunks, without ever sending a terminator byte, can keep the parser inside MINORNUMBERINTEGERDIGITS indefinitely. textBuffer.expandCurrentSegment() grows on every chunk, and validateIntegerLength is never invoked. The accumulator is only gated by maxStringLength (20 MiB default) — a ~20,000x amplification of the documented…

Published by the source

21 Jul 2026, 21:58 UTC

Last modified by the source

2 Oct 2026, 23:08 UTC

Source last checked

26 Oct 2026, 16:56 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-r7wm-3cxj-wff9

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# Patch Next advisory brief: CVE-2026-68494

Advisory: jackson-core: Async parser maxNumberLength bypass via chunked digit accumulation (incomplete fix for GHSA-72hv-8253-57qq)
IDs: CVE-2026-68494, GHSA-r7wm-3cxj-wff9
Record: https://patchnext.com/advisories/cve-2026-68494 (revision 1, 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 8.7)
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 2.21.4, 2.18.8; tools.jackson.core:jackson-core 3.1.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven com.fasterxml.jackson.core:jackson-core: affected < 2.18.8; >= 2.19.0, < 2.21.4; fixed in 2.21.4, 2.18.8
- Maven tools.jackson.core:jackson-core: affected >= 3.0.0, < 3.1.4; fixed in 3.1.4

## 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://github.com/advisories/GHSA-r7wm-3cxj-wff9 (GitHub-reviewed advisory GHSA-r7wm-3cxj-wff9 lists affected ranges: Maven com.fasterxml.jackson.core:jackson-core >=0 =2.19.0 =3.0.0 <3.1.4)

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