Linux Kernel up to 7.2-rc3 ipv4 net/ipv4/fib_trie.c fib_table_lookup use after free

CVSS Meta Temp Score
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CTI Interest Score
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8.7$5k-$25k1.22+

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 rated as very critical. Impacted is the function fib_table_lookup of the file net/ipv4/fib_trie.c of the component ipv4. Performing a manipulation results in use after free. This vulnerability is reported as CVE-2026-64572. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 6.6.147/6.12.100/6.18.41/7.1.5/7.2-rc3. This affects the function fib_table_lookup of the file net/ipv4/fib_trie.c of the component ipv4. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: free fib_alias with kfree_rcu() on insert error path fib_table_insert() publishes new_fa into the leaf's fa_list with fib_insert_alias() before calling the fib entry notifiers. When a notifier fails, the error path removes new_fa with fib_remove_alias() (hlist_del_rcu) and frees it right away with kmem_cache_free(). fib_table_lookup() walks that list under rcu_read_lock() only, so a concurrent lookup that already reached new_fa keeps reading it after the free: BUG: KASAN: slab-use-after-free in fib_table_lookup (net/ipv4/fib_trie.c:1601) Read of size 1 at addr ffff88810676d4eb by task exploit/297 Call Trace: fib_table_lookup (net/ipv4/fib_trie.c:1601) ip_route_output_key_hash_rcu (net/ipv4/route.c:2814) ip_route_output_key_hash (net/ipv4/route.c:2705) __ip4_datagram_connect (net/ipv4/datagram.c:49) udp_connect (net/ipv4/udp.c:2144) __sys_connect (net/socket.c:2167) __x64_sys_connect (net/socket.c:2173) do_syscall_64 entry_SYSCALL_64_after_hwframe which belongs to the cache ip_fib_alias of size 56 Triggering the error path needs CAP_NET_ADMIN and a registered fib notifier that can reject a route; a netdevsim device whose IPv4 FIB resource is exhausted is enough. Free new_fa with alias_free_mem_rcu(), as fib_table_delete() already does for a fib_alias removed from the trie.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-64572 since 07/19/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Additional levels of successful authentication are required for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (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 8150b5365f026e72250cacc527ea00be30f40105/d007056868723de9c0cc3f5ffaad47a8d468b9a4/cb8be318b4432abd88d3172ec157330f27a5f7a7/b8d2ea75c76abcd0d72679c2f488271f573e32fb/f2f152e94a67bc746afaf05a1b2702c195553112 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.1
VulDB Meta Temp Score: 8.7

VulDB Base Score: 9.1
VulDB Temp Score: 8.7
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 6.6.148/6.12.101/6.18.42/7.1.6/7.2-rc4
Patch: 8150b5365f026e72250cacc527ea00be30f40105/d007056868723de9c0cc3f5ffaad47a8d468b9a4/cb8be318b4432abd88d3172ec157330f27a5f7a7/b8d2ea75c76abcd0d72679c2f488271f573e32fb/f2f152e94a67bc746afaf05a1b2702c195553112

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-2026-64572 (🔒)
GCVE (CVE): GCVE-0-2026-64572
GCVE (VulDB): GCVE-100-386127

Entryinfo

Created: 08/05/2026 10:23
Changes: 08/05/2026 10:23 (60)
Complete: 🔍
Cache ID: 216::103

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