JSON::XS up to 4.04 Decode decode_hv resource consumption

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.26+

Summaryinfo

A vulnerability categorized as problematic has been discovered in JSON::XS up to 4.04. Affected by this issue is the function decode_hv of the component Decode. Such manipulation leads to resource consumption. This vulnerability is listed as CVE-2026-124539. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in JSON::XS up to 4.04. Affected by this issue is the function decode_hv of the component Decode. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource. Impacted is availability. CVE summarizes:

JSON::XS versions before 4.05 for Perl leak the decoded key of an object rejected for a missing colon in decode_hv. Unless it is short plain ASCII, a quoted key is decoded into a new scalar. Nothing frees that scalar when the object is rejected for a missing ':' after the key. A process that keeps running after a failed decode retains one key per rejected document, with its size chosen by the sender. Repeated requests exhaust process memory.

The advisory is available at metacpan.org. This vulnerability is handled as CVE-2026-124539 since 11/08/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 4.05 eliminates this vulnerability.

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Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: JSON::XS 4.05

Timelineinfo

11/08/2026 CVE reserved
11/14/2026 +6 days Advisory disclosed
11/14/2026 +0 days VulDB entry created
11/14/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: metacpan.org
Status: Confirmed

CNA: CPANSec
CVE: CVE-2026-124539 (🔒)

GCVE (CVE): GCVE-0-2026-124539
GCVE (VulDB): GCVE-100-437438

Entryinfo

Created: 11/14/2026 13:15
Changes: 11/14/2026 13:15 (54)
Complete: 🔍
Cache ID: 216::103

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