VDB-380529 · CVE-2026-63996 · GCVE-0-2026-63996

Linux Kernel Cmis cmis_cdb_process_reply rpl_len/rpl_exp_len out-of-bounds write

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.
8.8	$5k-$25k	2.16

Summaryinfo

A vulnerability identified as very critical has been detected in Linux Kernel. The affected element is the function cmis_cdb_process_reply of the component Cmis. Performing a manipulation of the argument rpl_len/rpl_exp_len results in out-of-bounds write. This vulnerability is cataloged as CVE-2026-63996. The attack must be initiated from a local position. There is no exploit available.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel (affected version not known). This affects the function cmis_cdb_process_reply of the component Cmis. The manipulation of the argument rpl_len/rpl_exp_len with an unknown input leads to a out-of-bounds write vulnerability. CWE is classifying the issue as CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability.

This vulnerability is uniquely identified as CVE-2026-63996. The exploitability is told to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/19/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

Operating System

Vendor

Linux

Name

Kernel

License

open-source

Website

Vendor: https://www.kernel.org/

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.8

VulDB Base Score: 8.8
VulDB Temp Score: 8.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

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

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/19/2026 Advisory disclosed
07/19/2026 +0 days VulDB entry created
07/19/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Status: Not defined

CVE: CVE-2026-63996 (🔒)
GCVE (CVE): GCVE-0-2026-63996
GCVE (VulDB): GCVE-100-380529

Entryinfo

Created: 07/19/2026 21:15
Changes: 07/19/2026 21:15 (50)
Complete: 🔍
Cache ID: 216::103