Linux Kernel up to 7.2-rc1 TIPC tipc_bcast_sync_rcv out-of-bounds

CVSS Meta Temp Score
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CTI Interest Score
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9.5$0-$5k3.10-

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2-rc1. It has been classified as very critical. This issue affects the function tipc_bcast_sync_rcv of the component TIPC. The manipulation leads to out-of-bounds. This vulnerability is referenced as CVE-2026-64450. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2-rc1. It has been rated as very critical. This issue affects the function tipc_bcast_sync_rcv of the component TIPC. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: tipc: fix out-of-bounds read in broadcast Gap ACK blocks A broadcast PROTOCOL/STATE_MSG can carry a Gap ACK blocks record in its data area. tipc_get_gap_ack_blks() only verifies that the record's len field is self-consistent with its ugack_cnt/bgack_cnt counts (sz == struct_size(p, gacks, ugack_cnt + bgack_cnt)); it does not check that the record actually fits in the message data area, msg_data_sz(). The unicast caller tipc_link_proto_rcv() bounds it ("if (glen > dlen) break;"), but the broadcast caller tipc_bcast_sync_rcv() discards the returned size, so tipc_link_advance_transmq() copies the record off the receive skb with an attacker-controlled count: this_ga = kmemdup(ga, struct_size(ga, gacks, ga->bgack_cnt), GFP_ATOMIC); A TIPC neighbour that negotiated TIPC_GAP_ACK_BLOCK triggers it with one ordinary broadcast STATE_MSG (msg_bc_ack_invalid() clear), sized so its data area is short, carrying a Gap ACK record with len = 0x400, bgack_cnt = 0xff and ugack_cnt = 0. len then equals struct_size(p, gacks, 255), so the consistency check passes and ga is non-NULL; kmemdup() reads struct_size(ga, gacks, 255) = 1024 bytes out of the much smaller skb: BUG: KASAN: slab-out-of-bounds in kmemdup_noprof+0x48/0x60 Read of size 1024 at addr ffff0000c7030d38 by task poc864/69 Call trace: kmemdup_noprof+0x48/0x60 tipc_link_advance_transmq+0x86c/0xb80 tipc_link_bc_ack_rcv+0x19c/0x1e0 tipc_bcast_sync_rcv+0x1c4/0x2c4 tipc_rcv+0x85c/0x1340 tipc_l2_rcv_msg+0xac/0x104 The buggy address belongs to the object at ffff0000c7030d00 which belongs to the cache skbuff_small_head of size 704 The buggy address is located 56 bytes inside of allocated 704-byte region [ffff0000c7030d00, ffff0000c7030fc0) The copied-out bytes are subsequently consumed as gap/ack values, but the read is already out of bounds at the kmemdup() regardless of how they are used. The unicast STATE path drops such a message: "if (glen > dlen) break;" skips the rest of STATE_MSG handling and the skb is freed. Make the broadcast path drop it too. tipc_bcast_sync_rcv() now bounds the record against msg_data_sz() and, when it does not fit, reports it back through tipc_node_bc_sync_rcv() to tipc_rcv() so the skb is discarded rather than processed. ga is not cleared on this path: ga == NULL already means "legacy peer without Selective ACK", a distinct legitimate state.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-64450 since 07/19/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/25/2026).

Upgrading to version 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4 or 7.2-rc2 eliminates this vulnerability. Applying the patch 055663d21dc4336f67933ab26bef3c5934be6324/016f5995c37a5a2c45198308f830f244517d70b7/74b45af86a767594ba52330cd440ea84e24d700d/9a51115fcdc78687c8852bf93a1db3951dbb223b/a21ed5064217cc33726da6c7ef1a520eba43aea1/2de42e268174766cb2e2b90721afdfdff70e0d8d/f333b6851bdf326fd2134133272dbbed0c94d921/2b66974a1b6134a4bbc3bfed181f7418f688eb54 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: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
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: Out-of-bounds
CWE: CWE-125 / CWE-119
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 5.10.261/5.15.212/6.1.178/6.6.145/6.12.96/6.18.39/7.1.4/7.2-rc2
Patch: 055663d21dc4336f67933ab26bef3c5934be6324/016f5995c37a5a2c45198308f830f244517d70b7/74b45af86a767594ba52330cd440ea84e24d700d/9a51115fcdc78687c8852bf93a1db3951dbb223b/a21ed5064217cc33726da6c7ef1a520eba43aea1/2de42e268174766cb2e2b90721afdfdff70e0d8d/f333b6851bdf326fd2134133272dbbed0c94d921/2b66974a1b6134a4bbc3bfed181f7418f688eb54

Timelineinfo

07/19/2026 CVE reserved
07/25/2026 +6 days Advisory disclosed
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64450 (🔒)
GCVE (CVE): GCVE-0-2026-64450
GCVE (VulDB): GCVE-100-383255

Entryinfo

Created: 07/25/2026 18:57
Changes: 07/25/2026 18:57 (59)
Complete: 🔍
Cache ID: 216::103

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