jackson-core: ReDoS: quadratic backtracking in NumberInput.PATTERN_FLOAT via looksLikeValidNumber()

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-2026-89407: 0.63% estimated exploitation activity in the next 30 days; percentile 50.14 (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 with a clean, textbook empirical signature: measured runtime grew almost exactly 4x for every doubling of input size across five consecutive doublings (5,000 → 160,000 characters), confirming O(n²) behavior. A single 160,000-character string (smaller than a typical HTTP request body) took 74.4 seconds for one call to NumberInput.looksLikeValidNumber(). 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/io/NumberInput.java (PATTERNFLOAT line ~41-42, PATTERNFLOATTRAILINGDOT line ~51, entry point looksLikeValidNumber() lines ~646-656) Technical Analysis PATTERNFLOAT contains ambiguous, adjacent quantifiers over the identical character class: [0-9] (optional digits), an optional [.], then [0-9]+ (required digits). Java's backtracking Pattern/Matcher engine has no possessive quantifiers or atomic grouping here, so on a non-matching input…

Published by the source

1 Oct 2026, 15:19 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-p6pp-m3f8-5c89

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-p6pp-m3f8-5c89

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# Patch Next advisory brief: CVE-2026-89407

Advisory: jackson-core: ReDoS: quadratic backtracking in NumberInput.PATTERN_FLOAT via looksLikeValidNumber()
IDs: CVE-2026-89407, GHSA-p6pp-m3f8-5c89
Record: https://patchnext.com/advisories/cve-2026-89407 (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 3.2.2, 3.1.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven com.fasterxml.jackson.core:jackson-core: affected >= 2.17.0, <= 2.18.10; >= 2.19.0, <= 2.21.6; >= 2.22.0, <= 2.22.2; 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, <= 3.2.1; fixed in 3.2.2, 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-p6pp-m3f8-5c89 (OSV record GHSA-p6pp-m3f8-5c89 lists affected ranges: Maven com.fasterxml.jackson.core:jackson-core >=2.17.0 =2.19.0 =2.22.0 =3.0.0 =3.2.0 <3.2.2 (fixed))
- Verified: https://github.com/advisories/GHSA-p6pp-m3f8-5c89 (GitHub-reviewed advisory GHSA-p6pp-m3f8-5c89 lists affected ranges: Maven com.fasterxml.jackson.core:jackson-core >=2.17.0 =2.19.0 =2.22.0 =3.0.0 =3.2.0 <=3.2.1)

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