CVE-2026-64390: ksmbd: track the connection owning a byte-range lock
Vulnerability summary
CVE-2026-64390 is a high (CVSS 8.8) vulnerability in linux. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 40.5% 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 23 · Related 21Timeline
- 25-07-2026PublishedVulnerability first disclosed.
- 17-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: track the connection owning a byte-range lock SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request. The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock. With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file. The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to. A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects. Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked. Use that connection and its llist_lock for unlock, rollback, close, and durable preserve. Durable reconnect assigns the new connection as the owner when publishing the locks again.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.47%
Chance of exploitation in the next 30 days
Percentile
41%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.47% 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, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu157 products
- linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-147.147 | < 7.0.0-31.31
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1067.70 | < 7.0.0-1012.12
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Debian2 products
- linux< 6.1.180-1 | < 6.12.100-1 | < 7.1.4-1
- linux-6.12< 6.12.100-1~deb12u1
Linux2 products
- linux≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 22d38cf75b556c20b039743bdf3654d535b858be | ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 66eb3643164e5e1029907793926c132f8b5c6148 | ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < ea5c9bf99f626a15cc59f645dc895f2b3f01992e | ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < fe20d492a69a6f79e637f438072b212e21ed3b78 | ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 427faaa52b0b399940c1a88065a5c310d10dad15 | ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < 5fecc15a30cb9ebd310f7b52c1ab607edcea78f6 | ≥ f5a544e3bab78142207e0242d22442db85ba1eff, < c1016dd1d8b2bcd1158bbaabe94a31bb7e7431fb | 5.15
- linux_kernel≥ 5.15, < 5.15.212 | ≥ 5.16, < 6.1.178 | ≥ 6.2, < 6.6.145 | ≥ 6.7, < 6.12.97 | ≥ 6.13, < 6.18.40 | ≥ 6.19, < 7.1.4
3 vendors · 161 products
