VDB-364997 · CVE-2026-45251 · EUVD-2026-31256

FreeBSD use after free

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.
7.6	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in FreeBSD and classified as critical. The affected element is an unknown function. The manipulation leads to use after free. This vulnerability is uniquely identified as CVE-2026-45251. Local access is required to approach this attack. No exploit exists. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability, which was classified as critical, has been found in FreeBSD (the affected version unknown). This issue affects an unknown part. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked thread does not hold a reference to the underlying object, this closure may result in the object being freed while the thread remains blocked. In this situation, the kernel must remove the blocked thread from the per-object wait queue prior to freeing the object. In the case of some file descriptor types, the kernel failed to unlink blocked threads from the object before freeing it. When the blocked thread is subsequently woken, it accesses memory that has already been freed resulting in a use-after-free vulnerability. The use-after-free vulnerability may be triggered by an unprivileged local user and can be exploited to obtain superuser privileges.

The weakness was disclosed by 75Acol, Lexpl0It, Fcgboy, Robinzeng2015 and Ryan. The advisory is shared at security.freebsd.org. The identification of this vulnerability is CVE-2026-45251 since 05/11/2026. The exploitation is known to be easy. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/24/2026).

Applying a patch is able to eliminate this problem.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-31256) and CERT Bund (WID-SEC-2026-1628). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

FreeBSD Project FreeBSD OS

Productinfo

Type

Operating System

Name

FreeBSD

License

open-source

Website

Product: https://www.freebsd.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.8
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.8
VulDB Temp Score: 7.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

ADP CISA Base Score: 7.8
ADP CISA Vector: 🔒

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: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

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: Patch
Status: 🔍

0-Day Time: 🔒

Timelineinfo

05/11/2026 CVE reserved
05/21/2026 +10 days Advisory disclosed
05/21/2026 +0 days VulDB entry created
05/24/2026 +3 days VulDB entry last update

Sourcesinfo

Product: freebsd.org

Advisory: security.freebsd.org
Researcher: 75Acol, Lexpl0It, Fcgboy, Robinzeng2015, Ryan
Status: Confirmed

CVE: CVE-2026-45251 (🔒)
GCVE (CVE): GCVE-0-2026-45251
GCVE (VulDB): GCVE-100-364997
EUVD: 🔒
CERT Bund: WID-SEC-2026-1628 - FreeBSD Project FreeBSD OS: Mehrere Schwachstellen

Entryinfo

Created: 05/21/2026 12:49
Updated: 05/24/2026 05:39
Changes: 05/21/2026 12:49 (53), 05/21/2026 14:53 (7), 05/21/2026 15:20 (1), 05/24/2026 05:39 (10)
Complete: 🔍
Cache ID: 216::103

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