CVE-2026-74259 (GCVE-0-2026-74259)
Vulnerability from cvelistv5
Published
2026-08-15 05:57
Modified
2026-08-17 05:45
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
cifs: remove all cifs files before kill super
Cifs files may be put into fileinfo_put_wq during umounting cifs.
After umount done, cifsFileInfo_put_final is called, which cause
following BUG:
BUG: kernel NULL pointer dereference, address: 0000000000000000
...
[ 134.222152] list_lru_add+0x64/0x1a0
[ 134.222399] ? cifs_put_tcon+0x171/0x340 [cifs]
[ 134.222772] d_lru_add+0x44/0x60
[ 134.222997] dput+0x1fc/0x210
[ 134.223213] cifsFileInfo_put_final+0x11a/0x140 [cifs]
[ 134.223576] process_one_work+0x17c/0x320
[ 134.223843] worker_thread+0x188/0x280
[ 134.224084] ? __pfx_worker_thread+0x10/0x10
[ 134.224366] kthread+0xcc/0x100
[ 134.224576] ? __pfx_kthread+0x10/0x10
[ 134.224827] ret_from_fork+0x30/0x50
[ 134.225063] ? __pfx_kthread+0x10/0x10
[ 134.225328] ret_from_fork_asm+0x1b/0x30
This can be reproduce by following:
unshare -n bash -c "
mkdir -p ${CIFS_MNT}
ip netns attach root 1
ip link add eth0 type veth peer veth0 netns root
ip link set eth0 up
ip -n root link set veth0 up
ip addr add 192.168.0.2/24 dev eth0
ip -n root addr add 192.168.0.1/24 dev veth0
ip route add default via 192.168.0.1 dev eth0
ip netns exec root sysctl net.ipv4.ip_forward=1
ip netns exec root iptables -t nat -A POSTROUTING -s 192.168.0.2 -o
${DEV} -j MASQUERADE
mount -t cifs ${CIFS_PATH} ${CIFS_MNT} -o
vers=3.0,sec=ntlmssp,credentials=${CIFS_CRED},rsize=65536,wsize=65536,cache=none,echo_interval=1
touch ${CIFS_MNT}/a.txt
ip netns exec root iptables -t nat -D POSTROUTING -s 192.168.0.2 -o
${DEV} -j MASQUERADE
"
umount ${CIFS_MNT}
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 708c276f516d27beaded7f372ac8111cee43926c Version: 0629a1a187e424373364d681b42b101894bdb548 Version: 0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd Version: f655467a9973f964b267871e5fef533ad5014494 Version: 340cea84f691c5206561bb2e0147158fe02070be Version: 340cea84f691c5206561bb2e0147158fe02070be Version: 30afc6ea72cc6cf7c8d579e79b64232801c38d08 Version: 6.1.167 ≤ Version: 6.6.130 ≤ Version: 6.12.78 ≤ Version: 6.18.20 ≤ Version: 6.19.10 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/client/connect.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "55fb9581986141659002264fdc75cef307811eb8",
"status": "affected",
"version": "708c276f516d27beaded7f372ac8111cee43926c",
"versionType": "git"
},
{
"lessThan": "4465ebe67d89345954bb3622b25dd13e06f9d367",
"status": "affected",
"version": "0629a1a187e424373364d681b42b101894bdb548",
"versionType": "git"
},
{
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"status": "affected",
"version": "0e4b8faaaebe3137bec5723ef2b3cb0437fb38fd",
"versionType": "git"
},
{
"lessThan": "21303c4a2b7275e626c6b67de0f45f2d5b9bb3e7",
"status": "affected",
"version": "f655467a9973f964b267871e5fef533ad5014494",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"status": "affected",
"version": "340cea84f691c5206561bb2e0147158fe02070be",
"versionType": "git"
},
{
"status": "affected",
"version": "30afc6ea72cc6cf7c8d579e79b64232801c38d08",
"versionType": "git"
},
{
"lessThan": "6.1.178",
"status": "affected",
"version": "6.1.167",
"versionType": "semver"
},
{
"lessThan": "6.6.145",
"status": "affected",
"version": "6.6.130",
"versionType": "semver"
},
{
"lessThan": "6.12.97",
"status": "affected",
"version": "6.12.78",
"versionType": "semver"
},
{
"lessThan": "6.18.40",
"status": "affected",
"version": "6.18.20",
"versionType": "semver"
},
{
"lessThan": "6.20",
"status": "affected",
"version": "6.19.10",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/smb/client/connect.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.0"
},
{
"lessThan": "7.0",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.178",
"versionStartIncluding": "6.1.167",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.145",
"versionStartIncluding": "6.6.130",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.97",
"versionStartIncluding": "6.12.78",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "6.18.20",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.5",
"versionStartIncluding": "7.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "7.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.19.10",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: remove all cifs files before kill super\n\nCifs files may be put into fileinfo_put_wq during umounting cifs.\nAfter umount done, cifsFileInfo_put_final is called, which cause\nfollowing BUG:\n\nBUG: kernel NULL pointer dereference, address: 0000000000000000\n...\n[ 134.222152] list_lru_add+0x64/0x1a0\n[ 134.222399] ? cifs_put_tcon+0x171/0x340 [cifs]\n[ 134.222772] d_lru_add+0x44/0x60\n[ 134.222997] dput+0x1fc/0x210\n[ 134.223213] cifsFileInfo_put_final+0x11a/0x140 [cifs]\n[ 134.223576] process_one_work+0x17c/0x320\n[ 134.223843] worker_thread+0x188/0x280\n[ 134.224084] ? __pfx_worker_thread+0x10/0x10\n[ 134.224366] kthread+0xcc/0x100\n[ 134.224576] ? __pfx_kthread+0x10/0x10\n[ 134.224827] ret_from_fork+0x30/0x50\n[ 134.225063] ? __pfx_kthread+0x10/0x10\n[ 134.225328] ret_from_fork_asm+0x1b/0x30\n\nThis can be reproduce by following:\nunshare -n bash -c \"\nmkdir -p ${CIFS_MNT}\nip netns attach root 1\nip link add eth0 type veth peer veth0 netns root\nip link set eth0 up\nip -n root link set veth0 up\nip addr add 192.168.0.2/24 dev eth0\nip -n root addr add 192.168.0.1/24 dev veth0\nip route add default via 192.168.0.1 dev eth0\nip netns exec root sysctl net.ipv4.ip_forward=1\nip netns exec root iptables -t nat -A POSTROUTING -s 192.168.0.2 -o\n${DEV} -j MASQUERADE\nmount -t cifs ${CIFS_PATH} ${CIFS_MNT} -o\nvers=3.0,sec=ntlmssp,credentials=${CIFS_CRED},rsize=65536,wsize=65536,cache=none,echo_interval=1\ntouch ${CIFS_MNT}/a.txt\nip netns exec root iptables -t nat -D POSTROUTING -s 192.168.0.2 -o\n${DEV} -j MASQUERADE\n\"\numount ${CIFS_MNT}"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.4,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The flaw is reached via the local CIFS client umount/teardown path (umount syscall through cifs_kill_sb/cifs_umount), not from remote SMB packet receive handling; network/server behavior only influences deferred close timing.\nAC:L - An attacker controls both sides by opening files, provoking server-close failures (malicious SMB server or induced network loss as in the repro), and triggering umount, repeatedly hitting the async workqueue race without external timing luck.\nPR:N - A malicious or compromised remote SMB/CIFS server needs no credentials or privileges on the victim host; it only needs the client to have mounted the share and later umount, while the attacker drives failing close responses over the existing session.\nUI:N - No victim interaction beyond an already-established mount is required for the malicious-server scenario; a local attacker can also self-drive mount/open/umount to trigger the bug without another user performing actions.\nS:U - Exploitation corrupts or crashes kernel memory on the same host during CIFS unmount cleanup; it does not cross VM, container, or IOMMU security boundaries.\nC:H - cifsFileInfo_put_final() dereferences dentry, inode, and cifsInodeInfo after kill_anon_super() destroyed the superblock, constituting use-after-free that can expose adjacent kernel heap contents beyond the observed NULL dereference.\nI:H - Post-teardown cifsFileInfo_put_final() performs list_del, lock teardown, and kfree on potentially freed cinode/file structures, enabling heap corruption and potential control-flow hijack primitives typical of kernel UAF bugs.\nA:H - The bug produces a kernel NULL pointer dereference/oops in list_lru_add during dentry LRU insertion in the fileinfo_put_wq worker, reliably crashing or destabilizing the host when triggered."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:45:08.700Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/55fb9581986141659002264fdc75cef307811eb8"
},
{
"url": "https://git.kernel.org/stable/c/4465ebe67d89345954bb3622b25dd13e06f9d367"
},
{
"url": "https://git.kernel.org/stable/c/3baedc9b2f53e6a6ac57b16fdff0f9b954d9ca71"
},
{
"url": "https://git.kernel.org/stable/c/21303c4a2b7275e626c6b67de0f45f2d5b9bb3e7"
},
{
"url": "https://git.kernel.org/stable/c/7839f1817a0cb6c4ed5cfe25d04845c43380a129"
},
{
"url": "https://git.kernel.org/stable/c/6d9a4aaaa8b2612b5ef9d581e2f286a458b71ee1"
}
],
"title": "cifs: remove all cifs files before kill super",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74259",
"datePublished": "2026-08-15T05:57:36.937Z",
"dateReserved": "2026-08-15T05:44:03.877Z",
"dateUpdated": "2026-08-17T05:45:08.700Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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