{"id":"DEBIAN-CVE-2025-21737","details":"In the Linux kernel, the following vulnerability has been resolved:  ceph: fix memory leak in ceph_mds_auth_match()  We now free the temporary target path substring allocation on every possible branch, instead of omitting the default branch.  In some cases, a memory leak occured, which could rapidly crash the system (depending on how many file accesses were attempted).  This was detected in production because it caused a continuous memory growth, eventually triggering kernel OOM and completely hard-locking the kernel.  Relevant kmemleak stacktrace:      unreferenced object 0xffff888131e69900 (size 128):       comm \"git\", pid 66104, jiffies 4295435999       hex dump (first 32 bytes):         76 6f 6c 75 6d 65 73 2f 63 6f 6e 74 61 69 6e 65  volumes/containe         72 73 2f 67 69 74 65 61 2f 67 69 74 65 61 2f 67  rs/gitea/gitea/g       backtrace (crc 2f3bb450):         [\u003cffffffffaa68fb49\u003e] __kmalloc_noprof+0x359/0x510         [\u003cffffffffc32bf1df\u003e] ceph_mds_check_access+0x5bf/0x14e0 [ceph]         [\u003cffffffffc3235722\u003e] ceph_open+0x312/0xd80 [ceph]         [\u003cffffffffaa7dd786\u003e] do_dentry_open+0x456/0x1120         [\u003cffffffffaa7e3729\u003e] vfs_open+0x79/0x360         [\u003cffffffffaa832875\u003e] path_openat+0x1de5/0x4390         [\u003cffffffffaa834fcc\u003e] do_filp_open+0x19c/0x3c0         [\u003cffffffffaa7e44a1\u003e] do_sys_openat2+0x141/0x180         [\u003cffffffffaa7e4945\u003e] __x64_sys_open+0xe5/0x1a0         [\u003cffffffffac2cc2f7\u003e] do_syscall_64+0xb7/0x210         [\u003cffffffffac400130\u003e] entry_SYSCALL_64_after_hwframe+0x77/0x7f  It can be triggered by mouting a subdirectory of a CephFS filesystem, and then trying to access files on this subdirectory with an auth token using a path-scoped capability:      $ ceph auth get client.services     [client.services]             key = REDACTED             caps mds = \"allow rw fsname=cephfs path=/volumes/\"             caps mon = \"allow r fsname=cephfs\"             caps osd = \"allow rw tag cephfs data=cephfs\"      $ cat /proc/self/mounts     services@[REDACTED].cephfs=/volumes/containers /ceph/containers ceph rw,noatime,name=services,secret=\u003chidden\u003e,ms_mode=prefer-crc,mount_timeout=300,acl,mon_addr=[REDACTED]:3300,recover_session=clean 0 0      $ seq 1 1000000 | xargs -P32 --replace={} touch /ceph/containers/file-{} && \\     seq 1 1000000 | xargs -P32 --replace={} cat /ceph/containers/file-{}  [ idryomov: combine if statements, rename rc to path_matched and make             it a bool, formatting ]","modified":"2026-08-27T23:05:11.866890747Z","published":"2025-02-27T03:15:14.327Z","upstream":["CVE-2025-21737"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2025-21737"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21737.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.15-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-21737.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}