Dashboard / CVE-2026-93990

CVE-2026-93990

HIGH
MEDIUM Priority: 0.04 BB Relevance: 77/100
Published: 2026-09-19 Modified: 2026-11-10 First seen: 2026-11-08 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: X
AT: None
VC: None
VI: High
VA: None

Description

Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that consume the following code unit, causing Expat to pass unpaired surrogates to applications built with XML_UNICODE and to silently replace input characters in other builds.

Weakness Classification (1)

Affected Software (2)

VendorProductVersion
libexpat libexpat 0 < 2.8.5
libexpat libexpat 0 < 2.8.5

References & Advisories (7)

Bug Bounty Relevance

77 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

8.7 / 10.0 v4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS — Exploitation Probability

0.41%
Raw Score 0.004130
Percentile 36.1%
Date 2026-11-13

EPSS Trend

2026-11-13
0.00413
2026-11-12
0.00413
2026-11-10
0.00403
2026-11-09
0.00403
2026-11-08
0.00403

Intelligence Sources

mitre ref →
nvd ref →

External Links