CVE-2026-33150 | libfuse up to 3.18.1 FUSE File Parser fuse_uring_start use after free (GHSA-qxv7-xrc2-qmfx)

VDB-352129 · CVE-2026-33150 · GHSA-QXV7-XRC2-QMFX LIBFUSE UP TO 3.18.1 FUSE FILE PARSER FUSE_URING_START USE AFTER FREE HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 7.6 $0-$5k 1.52+ Summaryinfo A vulnerability, which was classified as critical, has been found in libfuse up to 3.18.1. This affects the function fuse_uring_start of the component FUSE File Parser. This manipulation causes use after free. The identification of this vulnerability is CVE-2026-33150. The attack can only be executed locally. There is no exploit available. It is advisable to upgrade the affected component. Detailsinfo A vulnerability has been found in libfuse up to 3.18.1 and classified as critical. Affected by this vulnerability is the function fuse_uring_start of the component FUSE File Parser. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is: libfuse is the reference implementation of the Linux FUSE. From version 3.18.0 to before version 3.18.2, a use-after-free vulnerability in the io_uring subsystem of libfuse allows a local attacker to crash FUSE filesystem processes and potentially execute arbitrary code. When io_uring thread creation fails due to resource exhaustion (e.g., cgroup pids.max), fuse_uring_start() frees the ring pool structure but stores the dangling pointer in the session state, leading to a use-after-free when the session shuts down. The trigger is reliable in containerized environments where cgroup pids.max limits naturally constrain thread creation. This issue has been patched in version 3.18.2. The advisory is shared at github.com. This vulnerability is known as CVE-2026-33150 since 03/17/2026. The exploitation appears to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. Upgrading to version 3.18.2 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch 49fcd891a58f622c098e2ca67d66086f7b213836 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version. Productinfo Name libfuse Version 3.18.0 3.18.1 License open-source Website Product: https://github.com/libfuse/libfuse/ CPE 2.3info 🔒 🔒 CPE 2.2info 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 7.8 VulDB Meta Temp Score: 7.6 VulDB Base Score: 7.8 VulDB Temp Score: 7.5 VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA Base Score: 7.8 CNA Vector (GitHub_M): 🔒 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Use after free CWE: CWE-416 / CWE-119 CAPEC: 🔒 ATT&CK: 🔒 Physical: Partially Local: Yes Remote: No Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: libfuse 3.18.2 Patch: 49fcd891a58f622c098e2ca67d66086f7b213836 Timelineinfo 03/17/2026 CVE reserved 03/20/2026 +3 days Advisory disclosed 03/20/2026 +0 days VulDB entry created 03/20/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: GHSA-qxv7-xrc2-qmfx Status: Confirmed CVE: CVE-2026-33150 (🔒) GCVE (CVE): GCVE-0-2026-33150 GCVE (VulDB): GCVE-100-352129 Entryinfo Created: 03/20/2026 23:30 Changes: 03/20/2026 23:30 (68) Complete: 🔍 Cache ID: 99:745:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸