HIGH

CVE-2026-115506

libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay

CVSS v3

7.5

HIGH

EPSS Score

—

exploit probability

CISA KEV

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-115506 yet.

Full record on NVD

Description

libexpat through 2.9.0 contains a denial of service vulnerability because billion laughs protection in accountingDiffTolerated() in xmlparse.c detects entity amplification too late. Attackers can supply a moderately sized XML document with a large DTD and nested entity expansions to consume tens of seconds of CPU per parse.

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2026-10-22
Last Modified: 2026-10-22

Frequently asked questions

What is CVE-2026-115506?

Is CVE-2026-115506 actively exploited?

Active exploitation of CVE-2026-115506 has not been confirmed.

What is the CVSS score for CVE-2026-115506?

CVE-2026-115506 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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