CVE-2021-4454

Advisory lineage Upstream: 0 Downstream: 6
Analyzed
Published: 27 Mar 2025, 16:37
Last modified:23 May 2026, 15:18

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
0.03% LOW
0% probability -0.03%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

27 Mar 2025, 16:37
Published
Vulnerability first disclosed
23 May 2026, 15:18
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: can: j1939: fix errant WARN_ON_ONCE in j1939_session_deactivate The conclusion "j1939_session_deactivate() should be called with a session ref-count of at least 2" is incorrect. In some concurrent scenarios, j1939_session_deactivate can be called with the session ref-count less than 2. But there is not any problem because it will check the session active state before session putting in j1939_session_deactivate_locked(). Here is the concurrent scenario of the problem reported by syzbot and my reproduction log. cpu0 cpu1 j1939_xtp_rx_eoma j1939_xtp_rx_abort_one j1939_session_get_by_addr [kref == 2] j1939_session_get_by_addr [kref == 3] j1939_session_deactivate [kref == 2] j1939_session_put [kref == 1] j1939_session_completed j1939_session_deactivate WARN_ON_ONCE(kref < 2) ===================================================== WARNING: CPU: 1 PID: 21 at net/can/j1939/transport.c:1088 j1939_session_deactivate+0x5f/0x70 CPU: 1 PID: 21 Comm: ksoftirqd/1 Not tainted 5.14.0-rc7+ #32 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/2014 RIP: 0010:j1939_session_deactivate+0x5f/0x70 Call Trace: j1939_session_deactivate_activate_next+0x11/0x28 j1939_xtp_rx_eoma+0x12a/0x180 j1939_tp_recv+0x4a2/0x510 j1939_can_recv+0x226/0x380 can_rcv_filter+0xf8/0x220 can_receive+0x102/0x220 ? process_backlog+0xf0/0x2c0 can_rcv+0x53/0xf0 __netif_receive_skb_one_core+0x67/0x90 ? process_backlog+0x97/0x2c0 __netif_receive_skb+0x22/0x80

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.03%• Percentile: 9%

Affected Systems

  • linux•linux

    ≥ 7eef18c0479ba5d9f54fba30cd77c233ebca3eb1, < 6950df42a03c9ac9290503ced3f371199cb68fa9 | ≥ 55dd22c5d029423f513fd849e633adf0e9c10d0c, < b6d44072117bba057d50f7a2f96e5d070c65926d | ≥ 0c71437dd50dd687c15d8ca80b3b68f10bb21d63, < 9ab896775f98ff54b68512f345eed178bf961084 | ≥ 0c71437dd50dd687c15d8ca80b3b68f10bb21d63, < 1740a1e45eee65099a92fb502e1e67e63aad277d | ≥ 0c71437dd50dd687c15d8ca80b3b68f10bb21d63, < d0553680f94c49bbe0e39eb50d033ba563b4212d | 5e1fc537c1be332aef9621ca9146aeb3ba59522f | ≥ 5.4.138, < 5.4.232 | ≥ 5.10.56, < 5.10.168 | ≥ 5.13.8, < 5.14 | 5.14

  • linux•linux_kernel

    ≥ 5.4.138, < 5.4.232 | ≥ 5.10.56, < 5.10.168 | ≥ 5.13.8, < 5.14 | ≥ 5.14.1, < 5.15.93 | ≥ 5.16, < 6.1.11 | 5.14 | 5.14:rc4 | 5.14:rc5 | 5.14:rc6 | 5.14:rc7 | 6.2:rc1 | 6.2:rc2 | 6.2:rc3 | 6.2:rc4 | 6.2:rc5 | 6.2:rc6

References (5)