CVE-2026-64004: Linux kernel · net/iucv: fix locking in .getsockopt
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in cd691beafea0dd779e69e81ccc26b0ab50efcb5e : patch Linux kernel soon.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in cd691beafea0dd779e69e81ccc26b0ab50efcb5e, 9817369243380e287ebe5525411557eaa3aa2a79, 69554adc7a6fa04ede3ad7512321d83748e3c920 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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.
References
- git.kernel.org/stable/c/884eb247b74d86db97e3a37f0d6fc8e1e83590dd (opens in a new tab)
- git.kernel.org/stable/c/45bb8de8c95d8899f4b8f61bd9bceb8132af73cb (opens in a new tab)
- git.kernel.org/stable/c/1fc30bd4e55e2dd622d2d366cecd732c1841bbee (opens in a new tab)
- git.kernel.org/stable/c/cd691beafea0dd779e69e81ccc26b0ab50efcb5e (opens in a new tab)
- git.kernel.org/stable/c/6e792b8dd3002bbc4136745928a9605df1a72b8a (opens in a new tab)
- git.kernel.org/stable/c/9817369243380e287ebe5525411557eaa3aa2a79 (opens in a new tab)
- git.kernel.org/stable/c/69554adc7a6fa04ede3ad7512321d83748e3c920 (opens in a new tab)
- git.kernel.org/stable/c/3589d20a666caf30ad100c960a2de7de390fce88 (opens in a new tab)