CVE-2023-53794 (GCVE-0-2023-53794)
Vulnerability from cvelistv5 – Published: 2025-12-09 00:00 – Updated: 2026-08-05 09:16
VLAI
EPSS
VEX
Title
cifs: fix session state check in reconnect to avoid use-after-free issue
Summary
In the Linux kernel, the following vulnerability has been resolved:
cifs: fix session state check in reconnect to avoid use-after-free issue
Don't collect exiting session in smb2_reconnect_server(), because it
will be released soon.
Note that the exiting session will stay in server->smb_ses_list until
it complete the cifs_free_ipc() and logoff() and then delete itself
from the list.
Severity
9.8 (Critical)
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
4fcd1813e6404dd4420c7d12fb483f9320f0bf93 , < 7e4f5c3f01fb0e51ca438e43262d858daf9a0a76
(git)
Affected: 4fcd1813e6404dd4420c7d12fb483f9320f0bf93 , < 759ffc164d95a32c09528766d74d9b4fb054e8f4 (git) Affected: 4fcd1813e6404dd4420c7d12fb483f9320f0bf93 , < 99f280700b4cc02d5f141b8d15f8e9fad0418f65 (git) Affected: 655e0c067f0e02ece03fd0591dabe3db2ae27552 (git) Affected: 875cc09c0767a4ac06b57af383709657f98b3ea1 (git) Affected: 599fe1409085059ba12a2c3897c853be9fa9e7cf (git) Affected: 2e4378ee60049b752c9dce16f62ce6fbd11b379a (git) Affected: 59b520454b323ec43b2ae757217332cea33091e0 (git) Affected: e20c888e2b3576e5f498c167729d274ef60b86f8 (git) Affected: 4ce7aa4e44d88ce64ea8ae2337b8910f3670b0ba (git) Affected: 419fad68e4c4135ff9859e9214dd6cf954413ca1 (git) Affected: 3.10.103 , < 3.11 (semver) Affected: 3.12.63 , < 3.13 (semver) Affected: 3.14.74 , < 3.15 (semver) Affected: 3.16.37 , < 3.17 (semver) Affected: 3.18.37 , < 3.19 (semver) Affected: 4.1.28 , < 4.2 (semver) Affected: 4.4.16 , < 4.5 (semver) Affected: 4.6.5 , < 4.7 (semver) |
guessed | |
| Linux | Linux |
Affected:
4.7
Unaffected: 0 , < 4.7 (semver) Unaffected: 6.1.47 , ≤ 6.1.* (semver) Unaffected: 6.4.12 , ≤ 6.4.* (semver) Unaffected: 6.5 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
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"product": "Linux",
"programFiles": [
"fs/smb/client/smb2pdu.c"
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{
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{
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{
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"version": "3.18.37",
"versionType": "semver"
},
{
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"version": "4.1.28",
"versionType": "semver"
},
{
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"status": "affected",
"version": "4.4.16",
"versionType": "semver"
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{
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"version": "4.6.5",
"versionType": "semver"
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{
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"versions": [
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"version": "4.7"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.47",
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},
{
"lessThanOrEqual": "6.4.*",
"status": "unaffected",
"version": "6.4.12",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.5",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.47",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.4.12",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.5",
"versionStartIncluding": "4.7",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.10.103",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.12.63",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.14.74",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.16.37",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "3.18.37",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.1.28",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.4.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.6.5",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix session state check in reconnect to avoid use-after-free issue\n\nDon\u0027t collect exiting session in smb2_reconnect_server(), because it\nwill be released soon.\n\nNote that the exiting session will stay in server-\u003esmb_ses_list until\nit complete the cifs_free_ipc() and logoff() and then delete itself\nfrom the list."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The vulnerable code is the SMB/CIFS client\u0027s reconnect worker, whose execution and timing are dictated entirely by a remote SMB peer (TCP resets, malformed PDUs, STATUS_NETWORK_SESSION_EXPIRED, stalled SMB2_LOGOFF replies, DFS referrals). A malicious/compromised file server or an on-path attacker triggers it purely over TCP/445 with no local access.\nAC:L - The attacker controls both sides of the race: it stalls the SMB2_LOGOFF response to hold the session in SES_EXITING on smb_ses_list for the full response timeout, while forcing smb2_reconnect_server() to run on demand and repeatedly (it also self-requeues every 2 seconds), making the window trivially wide and the hit near-certain.\nPR:N - No credentials or privileges on the victim system are required \u2014 the attacker is the remote server (or an on-path attacker) acting against an existing mount, and the triggering conditions are protocol-level responses that require no authenticated privilege on the client.\nUI:N - Against an already-established mount (fstab, autofs, systemd automount, container share) the attack proceeds with no victim action; the session teardown side is generated by normal client activity such as DFS referral handling and session churn that the attacker itself induces.\nS:U - The freed and reused objects (struct cifs_ses, struct cifs_tcon) and the resulting corruption all live within the kernel\u0027s own security authority, with no crossing into a hypervisor, IOMMU, or other security scope.\nC:H - A use-after-free on a heap-allocated cifs_ses/cifs_tcon lets the attacker groom the freed slab and have the reconnect path read session fields (Suid, auth_key.response, chans[], dfs_root_ses) out of attacker-influenced memory, yielding a kernel information-disclosure primitive.\nI:H - The worker writes into the freed objects \u2014 list_add_tail() stores two pointers into ses-\u003erlist and the freed tcon_ipc-\u003erlist, ses_count is incremented through a dangling dfs_root_ses pointer, and cifs_setup_session() writes ses_status/Suid and frees ses-\u003eauth_key.response \u2014 giving write and controlled-free primitives usable for control-flow hijack.\nA:H - The use-after-free reliably corrupts kernel memory, taking spinlocks and mutexes inside a freed allocation and corrupting list heads, which oopses or panics the machine and can hang the cifs workqueue."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T09:16:01.824Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
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"url": "https://git.kernel.org/stable/c/7e4f5c3f01fb0e51ca438e43262d858daf9a0a76"
},
{
"url": "https://git.kernel.org/stable/c/759ffc164d95a32c09528766d74d9b4fb054e8f4"
},
{
"url": "https://git.kernel.org/stable/c/99f280700b4cc02d5f141b8d15f8e9fad0418f65"
}
],
"title": "cifs: fix session state check in reconnect to avoid use-after-free issue",
"x_generator": {
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}
}
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"assignerShortName": "Linux",
"cveId": "CVE-2023-53794",
"datePublished": "2025-12-09T00:00:51.061Z",
"dateReserved": "2025-12-08T23:58:35.274Z",
"dateUpdated": "2026-08-05T09:16:01.824Z",
"state": "PUBLISHED"
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"date": "2026-09-19",
"epss": "0.00511",
"percentile": "0.42549"
},
"nvd": {
"cve": {
"affected": [
{
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"product": "Linux",
"programFiles": [
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],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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{
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{
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{
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{
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"versionType": "git"
},
{
"status": "affected",
"version": "419fad68e4c4135ff9859e9214dd6cf954413ca1",
"versionType": "git"
},
{
"lessThan": "3.11",
"status": "affected",
"version": "3.10.103",
"versionType": "semver"
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{
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{
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},
{
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"status": "affected",
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"vendor": "Linux",
"versions": [
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"version": "4.7"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
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{
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"version": "6.1.47",
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"version": "6.4.12",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "6.5",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncifs: fix session state check in reconnect to avoid use-after-free issue\n\nDon\u0027t collect exiting session in smb2_reconnect_server(), because it\nwill be released soon.\n\nNote that the exiting session will stay in server-\u003esmb_ses_list until\nit complete the cifs_free_ipc() and logoff() and then delete itself\nfrom the list."
}
],
"id": "CVE-2023-53794",
"lastModified": "2026-08-04T10:19:21.410",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2025-12-09T01:16:50.957",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/759ffc164d95a32c09528766d74d9b4fb054e8f4"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7e4f5c3f01fb0e51ca438e43262d858daf9a0a76"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/99f280700b4cc02d5f141b8d15f8e9fad0418f65"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
},
"redhat_vex": {
"aggregate_severity": "Moderate",
"current_release_date": "2026-08-04T19:16:32+00:00",
"cve": "CVE-2023-53794",
"id": "CVE-2023-53794",
"initial_release_date": "2023-01-01T00:00:00+00:00",
"product_status:known_affected": "156",
"product_status:known_not_affected": "118",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: cifs: fix session state check in reconnect to avoid use-after-free issue",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53794.json",
"version": "3"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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