CVE-2026-4271Medium· 5.3▾ TwilightPoC availableA 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…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 29.2 · likelihood 0.2 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake. The CVSS score shown above comes from the assigning CNA record, not NVD.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CVEORG
Last analysed / modified upstream
0.9%
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).
libsoup3 (all versions)libsoup3 (all versions)libsoup3 (all versions)libsoup (all versions)libsouplibsouplibsoupRefer to the linked advisories for vendor-supplied fixes and affected version ranges.
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Connected by shared product, vendor, weakness, or advisory.
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