CVE-2025-40328: smb: client: fix potential UAF in smb2_close_cached_fid()
Vulnerability summary
CVE-2025-40328 is a high (CVSS 8.8) vulnerability in linux. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 39.9% of scored vulnerabilities.
Not severe (CVSS 8.8, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 30 · Related 28Timeline
- 09-12-2025PublishedVulnerability first disclosed.
- 30-10-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in smb2_close_cached_fid() find_or_create_cached_dir() could grab a new reference after kref_put() had seen the refcount drop to zero but before cfid_list_lock is acquired in smb2_close_cached_fid(), leading to use-after-free. Switch to kref_put_lock() so cfid_release() is called with cfid_list_lock held, closing that gap.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.46%
Chance of exploitation in the next 30 days
Percentile
40%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.46% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu129 products
- linux< 6.8.0-106.106 | < 6.17.0-14.14
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 6.8.0-1050.53 | < 6.17.0-1007.7
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian1 product
- linuxAll versions (No fix recorded) | < 6.12.63-1 | < 6.17.8-1
Linux1 product
- linux≥ ebe98f1447bbccf8228335c62d86af02a0ed23f7, < bb3355ce9dcaba1b4a766f98b2ad373cab6cd626 | ≥ ebe98f1447bbccf8228335c62d86af02a0ed23f7, < cb52d9c86d70298de0ab7c7953653898cbc0efd6 | ≥ ebe98f1447bbccf8228335c62d86af02a0ed23f7, < 065bd62412271a2d734810dd50336cae88c54427 | ≥ ebe98f1447bbccf8228335c62d86af02a0ed23f7, < bdb596ceb4b7c3f28786a33840263728217fbcf5 | ≥ ebe98f1447bbccf8228335c62d86af02a0ed23f7, < 734e99623c5b65bf2c03e35978a0b980ebc3c2f8 | 6.1
3 vendors · 131 products
