fraillt bitsery up to 5.2.4 std_smart_ptr.h loadFromSharedState improper validation of specified type of input

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.
6.6$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in fraillt bitsery up to 5.2.4. Affected by this vulnerability is the function loadFromSharedState in the library include/bitsery/ext/std_smart_ptr.h. Performing a manipulation results in improper validation of specified type of input. This vulnerability is identified as CVE-2026-9521. The attack can be initiated remotely. Additionally, an exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in fraillt bitsery up to 5.2.4. It has been classified as critical. This affects the function loadFromSharedState in the library include/bitsery/ext/std_smart_ptr.h. The manipulation with an unknown input leads to a improper validation of specified type of input vulnerability. CWE is classifying the issue as CWE-1287. The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type. This is going to have an impact on confidentiality, integrity, and availability.

The advisory is shared at gist.github.com. This vulnerability is uniquely identified as CVE-2026-9521. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details and a public exploit are known.

The exploit is shared for download at gist.github.com. It is declared as proof-of-concept.

Upgrading to version 5.2.5 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 66d16516e24893bebc1c8af52bf2fe9ad0735061 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-31780). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 6.6

VulDB Base Score: 7.3
VulDB Temp Score: 6.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

Exploitinginfo

Class: Improper validation of specified type of input
CWE: CWE-1287 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: bitsery 5.2.5
Patch: 66d16516e24893bebc1c8af52bf2fe9ad0735061

Timelineinfo

05/25/2026 Advisory disclosed
05/25/2026 +0 days VulDB entry created
05/26/2026 +1 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: gist.github.com
Status: Confirmed
Confirmation: 🔒

CVE: CVE-2026-9521 (🔒)
GCVE (CVE): GCVE-0-2026-9521
GCVE (VulDB): GCVE-100-365541
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 05/25/2026 21:22
Updated: 05/26/2026 06:21
Changes: 05/25/2026 21:22 (61), 05/26/2026 06:21 (1)
Complete: 🔍
Submitter: trebledj
Cache ID: 216::103

Submitinfo

Accepted

  • Submit #814457: fraillt bitsery 5.2.4 CWE-1287, CWE-843 (Type Confusion) (by trebledj)

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to know what is going to be exploited?

We predict KEV entries!