libexpat up to 2.8.0 XML algorithmic complexity

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.
4.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in libexpat up to 2.8.0. The affected element is an unknown function of the component XML Handler. The manipulation leads to algorithmic complexity. This vulnerability is traded as CVE-2026-45186. An attack has to be approached locally. There is no exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in libexpat up to 2.8.0 and classified as problematic. This issue affects an unknown functionality of the component XML Handler. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. Using CWE to declare the problem leads to CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. Impacted is availability. The summary by CVE is:

In libexpat before 2.8.1, the computational complexity of attribute name collision checks allows a denial of service via moderately sized crafted XML input.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-45186 since 05/10/2026. The exploitation is known to be difficult. An attack has to be approached locally. Neither technical details nor an exploit are publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 313709 (Linux Distros Unpatched Vulnerability : CVE-2026-45186), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.8.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (313709), EUVD (EUVD-2026-28985) and CERT Bund (WID-SEC-2026-1448). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Red Hat Enterprise Linux
  • SUSE openSUSE
  • Microsoft Azure Linux
  • Open Source expat

Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.3

VulDB Base Score: 2.5
VulDB Temp Score: 2.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

CNA Base Score: 2.9
CNA Vector (MITRE): 🔒

CVSSv2info

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

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

Exploitinginfo

Class: Algorithmic complexity
CWE: CWE-407 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 313709
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-45186

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: libexpat 2.8.1

Timelineinfo

05/10/2026 Advisory disclosed
05/10/2026 +0 days CVE reserved
05/10/2026 +0 days VulDB entry created
06/04/2026 +25 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-45186 (🔒)
GCVE (CVE): GCVE-0-2026-45186
GCVE (VulDB): GCVE-100-362489
EUVD: 🔒
CERT Bund: WID-SEC-2026-1448 - expat: Schwachstelle ermöglicht Denial of Service

Entryinfo

Created: 05/10/2026 09:01
Updated: 06/04/2026 06:38
Changes: 05/10/2026 09:01 (63), 05/10/2026 13:07 (1), 05/10/2026 22:05 (2), 05/18/2026 11:49 (11), 06/04/2026 06:38 (7)
Complete: 🔍
Cache ID: 216::103

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

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to stay up to date on a daily basis?

Enable the mail alert feature now!