CVE-2026-4271

HIGH
MEDIUM Priority: 0.07 BB Relevance: 75/100
Published: 2026-03-17 Modified: 2026-11-05 First seen: 2026-11-05 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: None
S: Unchanged
C: None
I: None
A: High

Description

A flaw was found in libsoup, a library for handling HTTP requests. This vulnerability, known as a Use-After-Free, occurs in the HTTP/2 server implementation. A remote attacker can exploit this by sending specially crafted HTTP/2 requests that cause authentication failures. This can lead to the application attempting to access memory that has already been freed, potentially causing application instability or crashes, resulting in a Denial of Service (DoS).

Weakness Classification (1)

References & Advisories (6)

https://access.redhat.com/errata/RHSA-2026:15968
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:17482
vendor-advisory x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:19143
vendor-advisory x_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2448044
issue-tracking x_refsource_REDHAT

Bug Bounty Relevance

75 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity
✓ No user interaction

CVSS Score

7.5 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploitation Probability

0.94%
Raw Score 0.009410
Percentile 61.5%
Date 2026-11-13

EPSS Trend

2026-11-13
0.00941
2026-11-12
0.00941
2026-11-10
0.00880
2026-11-09
0.00880
2026-11-08
0.00880
2026-11-07
0.00880
2026-11-06
0.00880
2026-11-05
0.00880

Intelligence Sources

mitre ref →
nvd ref →