CVE-2026-64004: linux Improper Locking
Vulnerability summary
CVE-2026-64004 is a high (CVSS 7.8) Improper Locking vulnerability in linux. EPSS estimates a 0.10% chance of exploitation in the next 30 days, higher than 0.8% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 31 · Related 31Timeline
- 19-07-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix locking in .getsockopt Mirror iucv_sock_setsockopt() and wrap the whole switch in lock_sock()/release_sock(). The pre-existing SO_MSGLIMIT-only lock becomes redundant and is removed. Any AF_IUCV HIPER user can potentially crash the kernel by racing recvmsg() with getsockopt(SO_MSGSIZE): the SO_MSGSIZE arm dereferences iucv->hs_dev->mtu after iucv_sock_close() (called from the racing recvmsg()) has set hs_dev to NULL, producing a NULL pointer dereference oops.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.10%
Chance of exploitation in the next 30 days
Percentile
1%
Versus all other CVEs
30-day change
-0.03 pp
From 0.13% on 20-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-667Improper LockingThe product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
- CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
Affected systems
Ubuntu167 products
- linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-146.146 | < 7.0.0-28.28
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1066.69 | < 7.0.0-1009.9
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 51363b8751a673a00ad48eea895266396d53fa52, < 884eb247b74d86db97e3a37f0d6fc8e1e83590dd | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < 45bb8de8c95d8899f4b8f61bd9bceb8132af73cb | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < 1fc30bd4e55e2dd622d2d366cecd732c1841bbee | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < cd691beafea0dd779e69e81ccc26b0ab50efcb5e | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < 6e792b8dd3002bbc4136745928a9605df1a72b8a | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < 9817369243380e287ebe5525411557eaa3aa2a79 | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < 69554adc7a6fa04ede3ad7512321d83748e3c920 | ≥ 51363b8751a673a00ad48eea895266396d53fa52, < 3589d20a666caf30ad100c960a2de7de390fce88 | 3.4
- linux_kernel≥ 3.4, < 5.10.259 | ≥ 5.11, < 5.15.210 | ≥ 5.16, < 6.1.176 | ≥ 6.2, < 6.6.143 | ≥ 6.7, < 6.12.93 | ≥ 6.13, < 6.18.35 | ≥ 6.19, < 7.0.12 | 7.1:rc1 | 7.1:rc2 | 7.1:rc3 | 7.1:rc4 | 7.1:rc5
Debian1 product
- linux< 6.1.176-1 | < 6.12.94-1 | < 7.0.12-1
3 vendors · 170 products
