CVE-2022-31117Network attack vector

Process crash via failed string-buffer reallocation

Published Jul 5, 2022 · Updated Apr 23, 2025

Double free in UltraJSON before 5.4.0 allows attackers to crash an embedding process when string-buffer reallocation fails. In decode_string, a failed realloc leaves ds->escStart unchanged, but the error path frees it before JSON_DecodeObject later frees the same pointer again. The Python bindings cannot reach this path; exposure requires direct use of the internal decoder and a buffer-growth allocation failure.

CVSS severity5.9
Medium
EPSS probability1.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Double free in UltraJSON before 5.4.0 allows attackers to crash an embedding process when string-buffer reallocation fails. In decode_string, a failed realloc leaves ds->escStart unchanged, but the error path frees it before JSON_DecodeObject later frees the same pointer again. The Python bindings cannot reach this path; exposure requires direct use of the internal decoder and a buffer-growth allocation failure.

The record

CVE
CVE-2022-31117
Published
Jul 5, 2022
Updated
Apr 23, 2025
Vendor
UltraJSON
Product
UltraJSON
Classifications
CWE-415, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 5, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

UltraJSON · UltraJSONversion=< 5.4.0

Published CVSS scores

4.3NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
5.9GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
5.9NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-415Double Free
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo