Cpanel::JSON::XS up to 4.79 Duplicate Key decode_hv memory leak

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.1$0-$5k1.36

Summaryinfo

A vulnerability classified as problematic was found in Cpanel::JSON::XS up to 4.79. The impacted element is the function decode_hv of the component Duplicate Key Handler. Executing a manipulation can lead to memory leak. This vulnerability is handled as CVE-2026-110677. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic was found in Cpanel::JSON::XS up to 4.79. This vulnerability affects the function decode_hv of the component Duplicate Key Handler. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. CVE summarizes:

Cpanel::JSON::XS versions from 4.28 before 4.80 for Perl leak the array collecting duplicate key values under dupkeys_as_arrayref in decode_hv. With dupkeys_as_arrayref, the values of a duplicate object key are collected into a new array. An extra reference is never released, so the array and every value in it outlive the decoded structure. The array also leaks when decoding fails after a duplicate key. Repeatedly decoding untrusted JSON with a duplicate key holding a large value exhausts process memory.

The advisory is available at github.com. This vulnerability was named CVE-2026-110677 since 10/14/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful 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 4.80 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

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
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Cpanel::JSON::XS 4.80

Timelineinfo

10/14/2026 CVE reserved
10/19/2026 +5 days Advisory disclosed
10/19/2026 +0 days VulDB entry created
10/19/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-110677 (🔒)
GCVE (CVE): GCVE-0-2026-110677
GCVE (VulDB): GCVE-100-422506

Entryinfo

Created: 10/19/2026 20:46
Changes: 10/19/2026 20:46 (56)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

Do you need the next level of professionalism?

Upgrade your account now!