CVE-2025-21777

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Validate the persistent meta data subbuf array The meta data for a mapped ring buffer contains an array of indexes of all the subbuffers. The first entry is the reader page, and the rest of the entries lay out the order of the subbuffers in how the ring buffer link list is to be created. The validator currently makes sure that all the entries are within the range of 0 and nr_subbufs. But it does not check if there are any duplicates. While working on the ring buffer, I corrupted this array, where I added duplicates. The validator did not catch it and created the ring buffer link list on top of it. Luckily, the corruption was only that the reader page was also in the writer path and only presented corrupted data but did not crash the kernel. But if there were duplicates in the writer side, then it could corrupt the ring buffer link list and cause a crash. Create a bitmask array with the size of the number of subbuffers. Then clear it. When walking through the subbuf array checking to see if the entries are within the range, test if its bit is already set in the subbuf_mask. If it is, then there is duplicates and fail the validation. If not, set the corresponding bit and continue.

• https://git.kernel.org/stable/c/0d547a6f5e8fad26ebc12f501d7d19fccdbad6bfPatch
• https://git.kernel.org/stable/c/3ec743d558f111d8999aea24577ba66c65ee2eebPatch
• https://git.kernel.org/stable/c/f5b95f1fa2ef3a03f49eeec658ba97e721412b32Patch

Published

Feb 27, 2025

Last Modified

Jun 17, 2026

Status

Analyzed

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2025-21771In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21772In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2025-21773In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21774In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21775In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21776In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21778In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21779In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21780In the Linux kernel, the following vulnerability has been re…7.8
• CVE-2025-21781In the Linux kernel, the following vulnerability has been re…5.5
• CVE-2025-21782In the Linux kernel, the following vulnerability has been re…7.1
• CVE-2025-21783In the Linux kernel, the following vulnerability has been re…5.5