CVE ID : CVE-2025-40209<\/p>\n
Published : Nov. 21, 2025, 10:19 a.m. | 56\u00a0minutes ago<\/p>\n
Description : In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation<\/p>\n
When btrfs_add_qgroup_relation() is called with invalid qgroup levels
\n(src >= dst), the function returns -EINVAL directly without freeing the
\npreallocated qgroup_list structure passed by the caller. This causes a
\nmemory leak because the caller unconditionally sets the pointer to NULL
\nafter the call, preventing any cleanup.<\/p>\n
The issue occurs because the level validation check happens before the
\nmutex is acquired and before any error handling path that would free
\nthe prealloc pointer. On this early return, the cleanup code at the
\n‘out’ label (which includes kfree(prealloc)) is never reached.<\/p>\n
In btrfs_ioctl_qgroup_assign(), the code pattern is:<\/p>\n
prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
\n ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc);
\n prealloc = NULL; \/\/ Always set to NULL regardless of return value
\n …
\n kfree(prealloc); \/\/ This becomes kfree(NULL), does nothing<\/p>\n
When the level check fails, ‘prealloc’ is never freed by either the
\ncallee or the caller, resulting in a 64-byte memory leak per failed
\noperation. This can be triggered repeatedly by an unprivileged user
\nwith access to a writable btrfs mount, potentially exhausting kernel
\nmemory.<\/p>\n
Fix this by freeing prealloc before the early return, ensuring prealloc
\nis always freed on all error paths.<\/p>\n
Severity: 0.0 | NA<\/p>\n
Visit the link for more details, such as CVSS details, affected products, timeline, and more…\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"
CVE ID : CVE-2025-40209 Published : Nov. 21, 2025, 10:19 a.m. | 56\u00a0minutes ago Description : In the Linux kernel, the following vulnerability has been resolved: btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation When btrfs_add_qgroup_relation() is called with invalid qgroup levels (src >= dst), the function returns -EINVAL directly without freeing the preallocated qgroup_list …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-74077","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/74077","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=74077"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/74077\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=74077"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=74077"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=74077"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}