CVE-2026-23248 | Linux Kernel up to 6.18.16/6.19.6/7.0-rc1 perf mmap use after free (EUVD-2026-12811)

VDB-351526 · CVE-2026-23248 · EUVD-2026-12811 LINUX KERNEL UP TO 6.18.16/6.19.6/7.0-RC1 PERF MMAP USE AFTER FREE HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 6.8 $5k-$25k 0.42+ Summaryinfo A vulnerability classified as critical was found in Linux Kernel up to 6.18.16/6.19.6/7.0-rc1. Affected is the function mmap of the component perf. Executing a manipulation can lead to use after free. This vulnerability is handled as CVE-2026-23248. There is not any exploit available. Upgrading the affected component is advised. Detailsinfo A vulnerability has been found in Linux Kernel up to 6.18.16/6.19.6/7.0-rc1 and classified as critical. This vulnerability affects the function mmap of the component perf. 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. CVE summarizes: In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix refcount bug and potential UAF in perf_mmap Syzkaller reported a refcount_t: addition on 0; use-after-free warning in perf_mmap. The issue is caused by a race condition between a failing mmap() setup and a concurrent mmap() on a dependent event (e.g., using output redirection). In perf_mmap(), the ring_buffer (rb) is allocated and assigned to event->rb with the mmap_mutex held. The mutex is then released to perform map_range(). If map_range() fails, perf_mmap_close() is called to clean up. However, since the mutex was dropped, another thread attaching to this event (via inherited events or output redirection) can acquire the mutex, observe the valid event->rb pointer, and attempt to increment its reference count. If the cleanup path has already dropped the reference count to zero, this results in a use-after-free or refcount saturation warning. Fix this by extending the scope of mmap_mutex to cover the map_range() call. This ensures that the ring buffer initialization and mapping (or cleanup on failure) happens atomically effectively, preventing other threads from accessing a half-initialized or dying ring buffer. The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-23248 since 01/13/2026. The exploitation appears to be difficult. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 03/18/2026). Upgrading to version 6.18.17, 6.19.7 or 7.0-rc2 eliminates this vulnerability. Applying the patch c27dea9f50ed525facb62ef647dddc4722456e07/ac7ecb65af170a7fc193e7bd8be15dac84ec6a56/77de62ad3de3967818c3dbe656b7336ebee461d2 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version. The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-12811). Productinfo Type Operating System Vendor Linux Name Kernel Version 6.18.0 6.18.1 6.18.2 6.18.3 6.18.4 6.18.5 6.18.6 6.18.7 6.18.8 6.18.9 6.18.10 6.18.11 6.18.12 6.18.13 6.18.14 6.18.15 6.18.16 6.19.0 6.19.1 6.19.2 6.19.3 6.19.4 6.19.5 6.19.6 7.0-rc1 License open-source Website Vendor: https://www.kernel.org/ CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 7.1 VulDB Meta Temp Score: 6.8 VulDB Base Score: 7.1 VulDB Temp Score: 6.8 VulDB Vector: 🔒 VulDB Reliability: 🔍 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: No Local: No Remote: Partially 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: Kernel 6.18.17/6.19.7/7.0-rc2 Patch: c27dea9f50ed525facb62ef647dddc4722456e07/ac7ecb65af170a7fc193e7bd8be15dac84ec6a56/77de62ad3de3967818c3dbe656b7336ebee461d2 Timelineinfo 01/13/2026 CVE reserved 03/18/2026 +64 days Advisory disclosed 03/18/2026 +0 days VulDB entry created 03/18/2026 +0 days VulDB entry last update Sourcesinfo Vendor: kernel.org Advisory: git.kernel.org Status: Confirmed CVE: CVE-2026-23248 (🔒) GCVE (CVE): GCVE-0-2026-23248 GCVE (VulDB): GCVE-100-351526 EUVD: 🔒 Entryinfo Created: 03/18/2026 12:01 Updated: 03/18/2026 12:24 Changes: 03/18/2026 12:01 (59), 03/18/2026 12:24 (1) Complete: 🔍 Cache ID: 99:9F5:101 Discussion No comments yet. 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