In the Linux kernel, the following vulnerability has been resolved:

tipc: fix use-after-free of the discoverer in tipc_disc_rcv()

bearer_disable() frees b->disc with tipc_disc_delete()'s plain kfree(),
but tipc_disc_rcv() still dereferences b->disc in RX softirq under
rcu_read_lock() (tipc_udp_recv -> tipc_rcv -> tipc_disc_rcv).

L2 bearers are safe thanks to the synchronize_net() in
tipc_disable_l2_media(), but the UDP bearer defers that call to the
cleanup_bearer() workqueue, so the discoverer is freed with no grace
period:

BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149)
Read of size 8 at addr ffff88802348b728 by task poc_tipc/184
<IRQ>
tipc_disc_rcv (net/tipc/discover.c:149)
tipc_rcv (net/tipc/node.c:2126)
tipc_udp_recv (net/tipc/udp_media.c:391)
udp_rcv (net/ipv4/udp.c:2643)
ip_local_deliver_finish (net/ipv4/ip_input.c:241)
</IRQ>
Freed by task 181:
kfree (mm/slub.c:6565)
bearer_disable (net/tipc/bearer.c:418)
tipc_nl_bearer_disable (net/tipc/bearer.c:1001)

The bearer is freed with kfree_rcu(); free the discoverer the same way.
Add an rcu_head to struct tipc_discoverer and free it and its skb from an
RCU callback.

Because the RCU callback (tipc_disc_free_rcu) lives in module text, a
call_rcu() that is still pending when the tipc module is unloaded would
invoke a freed function. Add an rcu_barrier() to tipc_exit() after the
bearer subsystem has been torn down, so all pending discoverer callbacks
have run before the module text goes away.

Reachable from an unprivileged user namespace: the TIPCv2 genl family is
netnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC
and CONFIG_TIPC_MEDIA_UDP.

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 affected < 5e215bf1c47fdddf8203a0fe80a0ed594065f101
25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 affected < ec7d54d8cc1723921d671e3272b427c96366506f
25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 affected < a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2
25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 affected < b65289e1c3f352a9f92c6e19713ddd647e033253
25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 affected < 1579342d71133da7f00daa02c75cebec7372097b
Linux Linux affected
Version Status Constraints
4.17 affected —
0 unaffected < 4.17
6.6.145 unaffected ≤ 6.6.*
6.12.97 unaffected ≤ 6.12.*
6.18.40 unaffected ≤ 6.18.*
7.1.5 unaffected ≤ 7.1.*
7.2-rc1 unaffected ≤ *

No data.

No data.

OpenCVE Enrichment is a feature of OpenCVE that uses AI to automatically link vendors and products to CVEs. Learn more on GitHub.

Vendors Products
Linux Subscribe
Linux Kernel Subscribe

Project Subscriptions

Vendors Products
Linux Subscribe
Linux Kernel Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://git.kernel.org/stable/c/1579342d71133da7f00daa02c75cebec7372097b cve-icon
https://git.kernel.org/stable/c/5e215bf1c47fdddf8203a0fe80a0ed594065f101 cve-icon
https://git.kernel.org/stable/c/a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2 cve-icon
https://git.kernel.org/stable/c/b65289e1c3f352a9f92c6e19713ddd647e033253 cve-icon
https://git.kernel.org/stable/c/ec7d54d8cc1723921d671e3272b427c96366506f cve-icon
History

Mon, 27 Jul 2026 20:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: tipc: fix use-after-free of the discoverer in tipc_disc_rcv() bearer_disable() frees b->disc with tipc_disc_delete()'s plain kfree(), but tipc_disc_rcv() still dereferences b->disc in RX softirq under rcu_read_lock() (tipc_udp_recv -> tipc_rcv -> tipc_disc_rcv). L2 bearers are safe thanks to the synchronize_net() in tipc_disable_l2_media(), but the UDP bearer defers that call to the cleanup_bearer() workqueue, so the discoverer is freed with no grace period: BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149) Read of size 8 at addr ffff88802348b728 by task poc_tipc/184 <IRQ> tipc_disc_rcv (net/tipc/discover.c:149) tipc_rcv (net/tipc/node.c:2126) tipc_udp_recv (net/tipc/udp_media.c:391) udp_rcv (net/ipv4/udp.c:2643) ip_local_deliver_finish (net/ipv4/ip_input.c:241) </IRQ> Freed by task 181: kfree (mm/slub.c:6565) bearer_disable (net/tipc/bearer.c:418) tipc_nl_bearer_disable (net/tipc/bearer.c:1001) The bearer is freed with kfree_rcu(); free the discoverer the same way. Add an rcu_head to struct tipc_discoverer and free it and its skb from an RCU callback. Because the RCU callback (tipc_disc_free_rcu) lives in module text, a call_rcu() that is still pending when the tipc module is unloaded would invoke a freed function. Add an rcu_barrier() to tipc_exit() after the bearer subsystem has been torn down, so all pending discoverer callbacks have run before the module text goes away. Reachable from an unprivileged user namespace: the TIPCv2 genl family is netnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC and CONFIG_TIPC_MEDIA_UDP.
Title tipc: fix use-after-free of the discoverer in tipc_disc_rcv()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-07-27T20:10:35.565Z

Reserved: 2026-07-19T15:36:31.795Z

Link: CVE-2026-64543

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-28T04:00:06Z

Weaknesses

No weakness.