CVE-2026-32874

HIGHPre-NVD 7.57.5
EchelonGraph scoreLOW confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: secondary
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Versions 5.4.0 through 5.11.0 contain an accumulating memory leak in JSON parsing large (outside of the range [-2^63, 2^64 - 1]) integers. The leaked memory is a copy of the string form of the integer plus an additional NULL byte. The leak occurs irrespective of whether the integer parses successfully or is rejected due to having more than sys.get_int_max_str_digits() digits, meaning that any sized leak per malicious JSON can be achieved provided that there is no limit on the overall size of the payload. Any service that calls ujson.load()/ujson.loads()/ujson.decode() on untrusted inputs is affected and vulnerable to denial of service attacks. This issue has been fixed in version 5.12.0.

CVSS v3
7.5
EG Score
7.5(low)
EPSS
38.0%
KEV
Not listed

Published

March 20, 2026

Last Modified

June 30, 2026

Advisory Details (6)

Auto-updated Jul 6, 2026
Patch available. Sources: github_release, github, redhat, github_commit.
redhat
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32874.json
redhat Patch Available

2449411 – (CVE-2026-32874) CVE-2026-32874 UltraJSON: UltraJSON: Denial of Service due to memory leak when parsing large integers

https://bugzilla.redhat.com/show_bug.cgi?id=2449411
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-32874
github Patch Available

Memory Leak parsing large integers allows DoS · Advisory · ultrajson/ultrajson · GitHub

https://github.com/ultrajson/ultrajson/security/advisories/GHSA-wgvc-ghv9-3pmm
github_release Patch Available

5.12.0

Patch available: ultrajson/ultrajson 5.12.0

https://github.com/ultrajson/ultrajson/releases/tag/5.12.0
github_commit Patch Available

commit 4baeb950df78 (ultrajson/ultrajson)

Patch available: ultrajson/ultrajson 5.12.0 (contains commit 4baeb950df78)

https://github.com/ultrajson/ultrajson/commit/4baeb950df780092bd3c89fc702a868e99a3a1d2

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupython3-ujson (5.10.0-1ubuntu0.1) @ questing2026-06-30ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
ujson5.10.0 ... 5.9.0 (8 versions)5.12.0—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 8× in last 7d / 15× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:15 UTCEPSS rescore
  4. 2026-07-07 13:46 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
  7. 2026-07-06 02:23 UTCEPSS rescore
  8. 2026-07-06 02:23 UTCEPSS rescore
  9. 2026-07-05 02:30 UTCEPSS rescore
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-01 15:06 UTCEPSS rescore
  12. 2026-06-30 23:22 UTCEPSS rescore
  13. 2026-06-30 04:38 UTCEG score recompute
  14. 2026-06-30 04:38 UTCVendor advisory
  15. 2026-06-30 04:32 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-32874?
CVE-2026-32874 is a high vulnerability published on March 20, 2026. UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Versions 5.4.0 through 5.11.0 contain an accumulating memory leak in JSON parsing large (outside of the range [-2^63, 2^64 - 1]) integers. The leaked memory is a copy of the string form of the integer plus…
When was CVE-2026-32874 disclosed?
CVE-2026-32874 was first published in the National Vulnerability Database on March 20, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-32874 actively exploited?
CVE-2026-32874 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 38.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-32874?
CVE-2026-32874 has a CVSS v3 base score of 7.5 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-32874?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-32874, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-32874

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