CVE-2026-74289

HIGHPre-NVD 7.87.8—
EchelonGraph scoreHIGH confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-15. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

ipv4: fib: Don't dump dying fib_info in fib_leaf_notify().

syzbot reported use-after-free in nsim_fib4_prepare_event(). [0]

The problem is that the following functions call fib_info_hold() / refcount_inc() while dumping fib_info under RCU, which is unsafe.

* mlxsw_sp_router_fib4_event() * rocker_router_fib_event() * nsim_fib4_prepare_event()

refcount_inc_not_zero() must be used, but it would be too late there.

Let's guarantee the lifetime of fib_info in fib_leaf_notify().

Note that IPv6 does not need the corresponding change since fib6_table_dump() holds fib6_table.tb6_lock.

[0]: refcount_t: addition on 0; use-after-free. WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25, CPU#0: kworker/u8:15/3420 Modules linked in: CPU: 0 UID: 0 PID: 3420 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: netns cleanup_net RIP: 0010:refcount_warn_saturate+0x9f/0x110 lib/refcount.c:25 Code: eb 66 85 db 74 3e 83 fb 01 75 4c e8 1b f1 22 fd 48 8d 3d 84 cb f1 0a 67 48 0f b9 3a eb 4a e8 08 f1 22 fd 48 8d 3d 81 cb f1 0a <67> 48 0f b9 3a eb 37 e8 f5 f0 22 fd 48 8d 3d 7e cb f1 0a 67 48 0f RSP: 0018:ffffc9000f2c7270 EFLAGS: 00010293 RAX: ffffffff84a18858 RBX: 0000000000000002 RCX: ffff888032ff9ec0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8f9353e0 RBP: 0000000000000000 R08: ffff888032ff9ec0 R09: 0000000000000005 R10: 0000000000000100 R11: 0000000000000004 R12: ffff8880570cc000 R13: dffffc0000000000 R14: ffff88802b40563c R15: ffff8880570cc000 FS: 0000000000000000(0000) GS:ffff888126173000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb1f4d5d000 CR3: 000000006072a000 CR4: 00000000003526f0 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] fib_info_hold include/net/ip_fib.h:629 [inline] nsim_fib4_prepare_event drivers/net/netdevsim/fib.c:930 [inline] nsim_fib_event_schedule_work drivers/net/netdevsim/fib.c:1000 [inline] nsim_fib_event_nb+0x1055/0x1240 drivers/net/netdevsim/fib.c:1043 call_fib_notifier+0x45/0x80 net/core/fib_notifier.c:25 call_fib_entry_notifier net/ipv4/fib_trie.c:90 [inline] fib_leaf_notify net/ipv4/fib_trie.c:2176 [inline] fib_table_notify net/ipv4/fib_trie.c:2194 [inline] fib_notify+0x36b/0x5e0 net/ipv4/fib_trie.c:2217 fib_net_dump net/core/fib_notifier.c:70 [inline] register_fib_notifier+0x184/0x360 net/core/fib_notifier.c:108 nsim_fib_create+0x85d/0x9f0 drivers/net/netdevsim/fib.c:1596 nsim_dev_reload_create drivers/net/netdevsim/dev.c:1604 [inline] nsim_dev_reload_up+0x374/0x7c0 drivers/net/netdevsim/dev.c:1058 devlink_reload+0x501/0x8d0 net/devlink/dev.c:475 devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:558 ops_pre_exit_list net/core/net_namespace.c:161 [inline] ops_undo_list+0x187/0x940 net/core/net_namespace.c:234 cleanup_net+0x56e/0x800 net/core/net_namespace.c:702 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

CVSS v3
7.8
EG Score
7.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

Advisory Details (2)

Auto-updated Aug 17, 2026
No patch confirmed yet.
generic

ipv4: fib: Don't dump dying fib_info in fib_leaf_notify(). - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/676482da8d938ea72c26da0fc86af2d2ec238ab2
generic

ipv4: fib: Don't dump dying fib_info in fib_leaf_notify(). - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/06b693d2eb6651a63ad85bad8673de3b7d4edd6d

Vendor Advisories for CVE-2026-74289(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 30× in last 7d / 30× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-21 00:19 UTCEG score recompute
  2. 2026-08-21 00:19 UTCGHSA enrichment
  3. 2026-08-20 22:56 UTCEPSS rescore
  4. 2026-08-20 11:27 UTCGHSA enrichment
  5. 2026-08-19 22:37 UTCEG score recompute
  6. 2026-08-19 22:37 UTCGHSA enrichment
  7. 2026-08-19 17:04 UTCEPSS rescore
  8. 2026-08-19 09:46 UTCGHSA enrichment
  9. 2026-08-18 20:56 UTCEG score recompute
  10. 2026-08-18 20:56 UTCGHSA enrichment
  11. 2026-08-18 13:49 UTCEPSS rescore
  12. 2026-08-18 13:49 UTCEPSS rescore
  13. 2026-08-18 08:05 UTCGHSA enrichment
  14. 2026-08-17 19:13 UTCEG score recompute
  15. 2026-08-17 19:13 UTCGHSA enrichment
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-17 06:22 UTCEG score recompute
  18. 2026-08-17 06:22 UTCGHSA enrichment
  19. 2026-08-17 05:56 UTCEG score recompute▲ 7.80
  20. 2026-08-17 05:56 UTCGHSA enrichment
  21. 2026-08-17 05:54 UTCMITRE cvelistV5CVSS v3 → 7.8 · severity → HIGH
  22. 2026-08-17 05:27 UTCEG score recompute
  23. 2026-08-17 05:27 UTCGHSA enrichment
  24. 2026-08-17 05:24 UTCMITRE cvelistV5
  25. 2026-08-16 14:56 UTCEPSS rescore
Show 5 more
  1. 2026-08-16 14:56 UTCEPSS rescore
  2. 2026-08-16 02:15 UTCEPSS rescore
  3. 2026-08-15 06:23 UTCNVD update
  4. 2026-08-15 06:16 UTCEG score recompute
  5. 2026-08-15 06:12 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-74289?
CVE-2026-74289 is a high vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: Don't dump dying fibinfo in fibleaf_notify(). syzbot reported use-after-free in nsimfib4prepare_event(). [0] The problem is that the following functions call fibinfohold() / refcountinc() while dumping fibinfo under RCU,…
When was CVE-2026-74289 disclosed?
CVE-2026-74289 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-74289 actively exploited?
CVE-2026-74289 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.8% of all scored CVEs.
What is the CVSS score of CVE-2026-74289?
CVE-2026-74289 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-74289?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-74289, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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