Soft lockup in Linux kernel atl1c driver from out-of-range read
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 6 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
The atl1c Ethernet driver in the Linux kernel, affected from 2.6.29 before the fixed releases, can loop forever when the hardware reports an out-of-range tpd_cons value of 0xffff while the PCIe link or MAC resets. This missing check for an impossible index in atl1c_clean_tx causes a soft lockup. The sources describe the trigger as a hardware reset and do not describe any attacker action.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
In the Linux kernel, the following vulnerability has been resolved: net: atl1c: fix soft lockup on out-of-range tpd_cons read The hardware can report an out-of-range tpd_cons (seen as 0xffff) while the PCIe link/MAC is resetting. An out-of-range value can never be reached and the loop below would spin forever. To avoid a soft lockup treat it as "nothing new to clean" instead. Reproduced on two machines, same NIC (Qualcomm Atheros AR8151 v2.0, 4-port), triggered by rebooting a Mikrotik CCR2004 PCIe card that the ports are directly linked to: - Ubuntu 26.04.1 LTS, kernel 7.0.0-31-generic. The link-flap precursor, before the lockup was captured with a full trace elsewhere: atl1c 0000:05:00.0 enp5s0f0: NETDEV WATCHDOG: CPU: 4: transmit queue 2 timed out 489984 ms atl1c 0000:05:00.0: MAC state machine can't be idle since disabled for 10ms second atl1c 0000:05:00.0: atl1c: enp5s0f0 NIC Link is Up<65535 Mbps Full Duplex> 65535 (0xffff) here is the same value tpd_cons reads back once the loop below gets stuck. - Proxmox VE, kernel 7.0.14-11-pve. Same NIC/trigger, this time caught by the soft lockup watchdog with a full stack trace: watchdog: BUG: soft lockup - CPU#12 stuck for 354s! [napi/eth%d-0:329] CPU: 12 UID: 0 PID: 329 Comm: napi/eth%d-0 Tainted: P O L 7.0.14-11-pve #1 PREEMPT(lazy) RIP: 0010:atl1c_clean_tx+0x142/0x2d0 [atl1c] Call Trace: <TASK> __napi_poll+0x32/0x1e0 napi_threaded_poll_loop+0x286/0x2e0 napi_threaded_poll+0xfd/0x140 kthread+0xf7/0x130 ret_from_fork+0x2da/0x3a0 ret_from_fork_asm+0x1a/0x30 </TASK>
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.29 and later | 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.29 and later Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3 Patch available CNA
Remediation
The Linux kernel is fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9 and 7.3. Red Hat Enterprise Linux 10, 7, 8, 9, OpenShift Container Platform 4 and other products are affected without a fix, and Red Hat's plan for them is none available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-18 Threatist record created from CVE-2026-98489
- 2026-10-18 Alias added: GHSA-v9fj-6g8j-jj53
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/e7acd4cdeccbcdfd407adeb72b1eba14d1145b6f
- https://git.kernel.org/stable/c/5ea2576a4f5ec476f33169fdbe9090d2b038ad13
- https://git.kernel.org/stable/c/4daf80da0c38b8cd92c111ad96cb38322aabf586
- https://git.kernel.org/stable/c/57b55367b6e3accc55a989afeaf127063e3614dc
- https://git.kernel.org/stable/c/9f2cc71a2e2799d9c993c73f1bd36507eef6ae43
- https://git.kernel.org/stable/c/586847400b1168a88917287ac02c2c91a620b841
- https://git.kernel.org/stable/c/d4ab263e40fcf7cfa38a43ec774067d32eb94e16
- https://git.kernel.org/stable/c/36c2009d90f2210ef92e6f4f2850e8b57b09e754
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Sources
- CVE-2026-98489 · CVE Program
- CVE-2026-98489 · NVD
- FIRST EPSS
- GHSA-v9fj-6g8j-jj53 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98489 · Red Hat security data · CC BY 4.0
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