nbd: don't allow reconnect after disconnect
In the Linux kernel, the following vulnerability has been resolved: nbd: don't allow reconnect after disconnect Following process can cause nbd_config UAF: 1) grab nbd_config temporarily; 2) nbd_genl_disconnect() flush all recv_work() and release the initial reference: nbd_genl_disconnect nbd_disconnect_and_put nbd_disconnect flush_workqueue(nbd->recv_workq) if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...)) nbd_config_put -> due to step 1), reference is still not zero 3) nbd_genl_reconfigure() queue recv_work() again; nbd_genl_reconfigure config = nbd_get_config_unlocked(nbd) if (!config) -> succeed if (!test_bit(NBD_RT_BOUND, ...)) -> succeed nbd_reconnect_socket queue_work(nbd->recv_workq, &args->work) 4) step 1) release the reference; 5) Finially, recv_work() will trigger UAF: recv_work nbd_config_put(nbd) -> nbd_config is freed atomic_dec(&config->recv_threads) -> UAF Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so that nbd_genl_reconfigure() will fail.
CVE-2025-21731
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-21731
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "e70a578487a47d7cf058904141e586684d1c3381",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "6bef6222a3f6c7adb6396f77f25a3579d821b09a",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "e3be8862d73cac833e0fb7602636c19c6cb94b11",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "e7343fa33751cb07c1c56b666bf37cfca357130e",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "d208d2c52b652913b5eefc8ca434b0d6b757f68f",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302",
"versionType": "git"
},
{
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"lessThan": "844b8cdc681612ff24df62cdefddeab5772fadf1",
"versionType": "git"
}
],
"programFiles": [
"drivers/block/nbd.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.12"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.12",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.4.291",
"versionType": "semver",
"lessThanOrEqual": "5.4.*"
},
{
"status": "unaffected",
"version": "5.10.235",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.179",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.129",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.76",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.13",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.13.2",
"versionType": "semver",
"lessThanOrEqual": "6.13.*"
},
{
"status": "unaffected",
"version": "6.14",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/block/nbd.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-21731
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #26926 · Revision 1
- Added to Heist Feed
- Publisher date