Linux Kernel up to 7.2-rc3 xfrm net/xfrm/xfrm_policy.c xfrm_hash_rebuild null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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6.2$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc3. It has been declared as critical. The impacted element is the function xfrm_hash_rebuild of the file net/xfrm/xfrm_policy.c of the component xfrm. Executing a manipulation can lead to null pointer dereference. This vulnerability is registered as CVE-2026-64579. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc3 and classified as critical. This vulnerability affects the function xfrm_hash_rebuild of the file net/xfrm/xfrm_policy.c of the component xfrm. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert xfrm_hash_rebuild()'s first loop preallocates the bins/chains the reinsert loop needs, so the reinsert (after hlist_del_rcu()) cannot allocate or fail. But its guard is inverted: it skips policies with prefixlen < threshold and preallocates for the rest. prefixlen < threshold is exactly when policy_hash_bysel() returns NULL and the reinsert takes the allocating xfrm_policy_inexact_insert() path. So the loop preallocates for the exact policies (which never allocate) and skips the inexact ones, whose bin/node is then allocated GFP_ATOMIC during reinsert. On failure the error path only WARN_ONCE()s and continues, leaving a poisoned bydst node; the next rebuild's hlist_del_rcu() dereferences LIST_POISON2 and takes a GPF. Reachable under memory pressure, deterministic via failslab. Invert the guard so preallocation covers exactly the reinserted policies; the reinsert then allocates nothing and cannot fail. Crash: Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI KASAN: maybe wild-memory-access in range [0xdead...] ... Workqueue: events xfrm_hash_rebuild RIP: 0010:xfrm_hash_rebuild+0x5b3/0x1190 RAX: dead000000000122 (LIST_POISON2 + offset) ... Call Trace: hlist_del_rcu (include/linux/rculist.h:599) xfrm_hash_rebuild (net/xfrm/xfrm_policy.c:1365) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) ret_from_fork_asm (arch/x86/entry/entry_64.S:245) ... Kernel panic - not syncing: Fatal exception in interrupt

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2026-64579 since 07/19/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/05/2026).

Upgrading to version 6.6.148, 6.12.101, 6.18.42, 7.1.6 or 7.2-rc4 eliminates this vulnerability. Applying the patch d9d9cc21cc90014724a14c447e3d587be9447107/94c00391a5117530188334f740ce26d3f1256190/7acc5ed2f33608a3d83b64f50a5766843b6e2485/6aa3796d18a9fda953ad76a62b57bf6c145cb9ef/f38f8cce2f7e79775b3db7e8a5eacda04ac908e4 is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-53273). Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

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 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc4
Patch: d9d9cc21cc90014724a14c447e3d587be9447107/94c00391a5117530188334f740ce26d3f1256190/7acc5ed2f33608a3d83b64f50a5766843b6e2485/6aa3796d18a9fda953ad76a62b57bf6c145cb9ef/f38f8cce2f7e79775b3db7e8a5eacda04ac908e4

Timelineinfo

07/19/2026 CVE reserved
08/05/2026 +17 days Advisory disclosed
08/05/2026 +0 days VulDB entry created
08/05/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64579 (🔒)
GCVE (CVE): GCVE-0-2026-64579
GCVE (VulDB): GCVE-100-386140
EUVD: 🔒

Entryinfo

Created: 08/05/2026 10:33
Updated: 08/05/2026 11:17
Changes: 08/05/2026 10:33 (60), 08/05/2026 11:17 (1)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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