CVE-2025-40084: ksmbd: transport_ipc: validate payload size before reading handle
Vulnerability summary
CVE-2025-40084 is a high (CVSS 7.1) vulnerability in linux. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 4.1% of scored vulnerabilities.
Not severe (CVSS 7.1, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 21 · Related 17Timeline
- 29-10-2025PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: transport_ipc: validate payload size before reading handle handle_response() dereferences the payload as a 4-byte handle without verifying that the declared payload size is at least 4 bytes. A malformed or truncated message from ksmbd.mountd can lead to a 4-byte read past the declared payload size. Validate the size before dereferencing. This is a minimal fix to guard the initial handle read.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- NVDNIST7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
EPSS trend
Probability
0.15%
Chance of exploitation in the next 30 days
Percentile
4%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.15% 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: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu142 products
- linuxAll versions (No fix recorded) | < 6.8.0-106.106 | < 6.17.0-14.14
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 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
- linux< 6.1.158-1 | < 6.12.57-1 | < 6.17.6-1
Linux1 product
- linux≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < a02e432d5130da4c723aabe1205bac805889fdb2 | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 2dc125f5da134c0915a840b62565c60a595673dd | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 898d527ed94c19980a4d848f10057f1fed578ffb | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 867ffd9d67285612da3f0498ca618297f8e41f01 | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 6f40e50ceb99fc8ef37e5c56e2ec1d162733fef0 | 5.15
3 vendors · 144 products
