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CVE-2026-74726

bonding: alb: re-check primary_is_promisc under RTNL in bond_alb_monitor

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

In the Linux kernel, the following vulnerability has been resolved: bonding: alb: re-check primary_is_promisc under RTNL in bond_alb_monitor bond_alb_monitor() reads primary_is_promisc under RCU, then drops RCU and takes RTNL via rtnl_trylock() before undoing the promiscuity it set on the active slave. In that window the active slave can change under RTNL (RTM_DELLINK -> __bond_release_one() -> bond_alb_handle_active_change()), which already drops the promiscuity and clears primary_is_promisc. The monitor still acts on the stale decision: if the slave was removed with no failover, curr_active_slave is now NULL and the deref faults; if it failed over, the stale dev_set_promiscuity(-1) underflows the new slave's promiscuity counter and pins it in IFF_PROMISC. Oops: general protection fault, probably for non-canonical address ... KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] Workqueue: b42 bond_alb_monitor RIP: 0010:bond_alb_monitor (drivers/net/bonding/bond_alb.c:1600) process_one_work (kernel/workqueue.c:3322) worker_thread (kernel/workqueue.c:3486) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:158) Kernel panic - not syncing: Fatal exception Re-check primary_is_promisc (and curr_active_slave) after taking RTNL so the monitor only undoes an increment it still owns. The other bonding monitors already re-read state under RTNL in their commit phase (bond_miimon_commit/bond_ab_arp_commit); bond_alb_monitor() was the only one acting on the pre-trylock decision.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in f7668762bf5fd6db9397de5c0514407489d9d815; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in 09add8d5cfa9c46828f51eaad162c36e86366b71; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in b82f51681a7a88c7d3c865e817a3340d42b5fa2a; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in dd148539fb4741d01c06b7d2c8bd84b01920756c; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in dccec0227ed8d9e36936d66e256b957dc2858468; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in 2faf75a8a06504071b4c0aea7e45a9cc49a4e187; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in 257c4a3a34d8f51efb00f35375a0c6ce3c8f6ce2; From d0e81b7e2246a41d068ecaf15aac9de570816d63 · fixed in 683c6ba6e58e6ed1037831ea97dd58d9c0e76b8d

  • Linux Linux

    2.6.24

  • KernelLinux

    From 2.6.24 · fixed in 5.10.265; From 5.11.0 · fixed in 5.15.216; From 5.16.0 · fixed in 6.1.183; From 6.2.0 · fixed in 6.6.152; From 6.7.0 · fixed in 6.12.104; From 6.13.0 · fixed in 6.18.45; From 6.19.0 · fixed in 7.1.9

References 8

git.kernel.org