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Review reviewHigh

CVE-2026-64543

Linux

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/discove...

CVSS
7.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.28
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.8

Vulnerability overview

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/discove...

Affected product and versions

Product
Linux
Affected versions
>= 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 < 5e215bf1c47fdddf8203a0fe80a0ed594065f101, >= 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 < ec7d54d8cc1723921d671e3272b427c96366506f, >= 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 < a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2, >= 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 < b65289e1c3f352a9f92c6e19713ddd647e033253, >= 25b0b9c4e835ffaa65b61c3efe2e28acf84d0259 < 1579342d71133da7f00daa02c75cebec7372097b, >= 4.17
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
Not available