0.0
NA
CVE-2026-64450
tipc: fix out-of-bounds read in broadcast Gap ACK blocks
Description

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.

INFO

Published Date :

July 25, 2026, 10:17 a.m.

Last Modified :

July 25, 2026, 10:17 a.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products

The following products are affected by CVE-2026-64450 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

Solution
Apply kernel patches to fix out-of-bounds read in broadcast Gap ACK blocks handling.
  • Update the Linux kernel to the patched version.
  • Ensure kernel is configured for TIPC_GAP_ACK_BLOCKS.
  • Review broadcast message handling logic.
  • Apply bounds checks for Gap ACK records.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-64450 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-64450 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-64450 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-64450 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Jul. 25, 2026

    Action Type Old Value New Value
    Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': '055663d21dc4336f67933ab26bef3c5934be6324', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': '016f5995c37a5a2c45198308f830f244517d70b7', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': '74b45af86a767594ba52330cd440ea84e24d700d', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': '9a51115fcdc78687c8852bf93a1db3951dbb223b', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': 'a21ed5064217cc33726da6c7ef1a520eba43aea1', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': '2de42e268174766cb2e2b90721afdfdff70e0d8d', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': 'f333b6851bdf326fd2134133272dbbed0c94d921', 'versionType': 'git'}, {'status': 'affected', 'version': 'd7626b5acff9227e2a65da636a53e09bdafdc0aa', 'lessThan': '2b66974a1b6134a4bbc3bfed181f7418f688eb54', 'versionType': 'git'}], 'programFiles': ['net/tipc/bcast.c', 'net/tipc/bcast.h', 'net/tipc/node.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '5.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '5.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.96', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/tipc/bcast.c', 'net/tipc/bcast.h', 'net/tipc/node.c'], 'defaultStatus': 'affected'}]
    Added Description 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.
    Added Reference https://git.kernel.org/stable/c/016f5995c37a5a2c45198308f830f244517d70b7
    Added Reference https://git.kernel.org/stable/c/055663d21dc4336f67933ab26bef3c5934be6324
    Added Reference https://git.kernel.org/stable/c/2b66974a1b6134a4bbc3bfed181f7418f688eb54
    Added Reference https://git.kernel.org/stable/c/2de42e268174766cb2e2b90721afdfdff70e0d8d
    Added Reference https://git.kernel.org/stable/c/74b45af86a767594ba52330cd440ea84e24d700d
    Added Reference https://git.kernel.org/stable/c/9a51115fcdc78687c8852bf93a1db3951dbb223b
    Added Reference https://git.kernel.org/stable/c/a21ed5064217cc33726da6c7ef1a520eba43aea1
    Added Reference https://git.kernel.org/stable/c/f333b6851bdf326fd2134133272dbbed0c94d921
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.