Linux Kernel up to 6.18.41/7.1.5/7.2-rc4 rhashtable lib/rhashtable.c rhashtable_walk_next use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k2.57+

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.18.41/7.1.5/7.2-rc4. This affects the function rhashtable_walk_next of the file lib/rhashtable.c of the component rhashtable. Such manipulation of the argument p leads to use after free. This vulnerability is uniquely identified as CVE-2026-64563. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.41/7.1.5/7.2-rc4 and classified as very critical. Affected by this issue is the function rhashtable_walk_next of the file lib/rhashtable.c of the component rhashtable. The manipulation of the argument p with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: rhashtable: clear stale iter->p on table restart rhashtable_walk_start_check() has two restart paths when resuming a walk. When iter->walker.tbl is valid, it re-validates iter->p against the table and sets iter->p = NULL if the object is gone. When iter->walker.tbl is NULL (table was freed during resize), it resets slot and skip but forgets to clear iter->p. rhashtable_walk_next() then dereferences the stale iter->p, reading freed memory. This is a use-after-free. Any caller that does multi-fragment rhashtable walks across walk_stop/walk_start boundaries is affected. Concrete cases include netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC (tipc_nl_sk_walk in net/tipc/socket.c). Crash stack (netlink_diag): BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0 Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080) Call Trace: rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016) __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122) netlink_diag_dump+0xc2/0x240 netlink_dump+0x5bc/0x1270 netlink_recvmsg+0x7a3/0x980 sock_recvmsg+0x1bc/0x200 __sys_recvfrom+0x1d4/0x2c0

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-64563 since 07/19/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 08/04/2026).

Upgrading to version 6.18.42, 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch 3ff7c1dbf722cf3fa538672452ba182318e0fcc3/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-52604). Once again VulDB remains the best source for vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.42/7.1.6/7.2-rc5
Patch: 3ff7c1dbf722cf3fa538672452ba182318e0fcc3/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456

Timelineinfo

07/19/2026 CVE reserved
08/04/2026 +16 days Advisory disclosed
08/04/2026 +0 days VulDB entry created
08/04/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64563 (🔒)
GCVE (CVE): GCVE-0-2026-64563
GCVE (VulDB): GCVE-100-385772
EUVD: 🔒

Entryinfo

Created: 08/04/2026 09:06
Updated: 08/04/2026 09:16
Changes: 08/04/2026 09:06 (61), 08/04/2026 09:16 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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