PatchSiren cyber security CVE debrief
CVE-2026-43410 Linux CVE debrief
CVE-2026-43410 is a Linux kernel availability vulnerability in the Stratix10 Remote System Update (RSU) driver. When RSU is not enabled in the First Stage Boot Loader (FSBL), the driver can continue after a failed async message send, later dereference an invalid channel, and panic the kernel. NVD rates the issue as CVSS 3.1 5.5/Medium with local attack requirements and high availability impact only.
- Vendor
- Linux
- Product
- Unknown
- CVSS
- MEDIUM 5.5
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-08
- Original CVE updated
- 2026-05-21
- Advisory published
- 2026-05-08
- Advisory updated
- 2026-05-21
Who should care
Linux kernel maintainers, distro security teams, and operators of Intel/Altera SoCFPGA Stratix 10 systems that include the stratix10-rsu driver should care most. This is especially relevant where firmware or FSBL configurations may leave RSU disabled, because the issue is triggered by that runtime state rather than by network exposure.
Technical summary
The reported bug is a NULL pointer dereference in firmware: stratix10-rsu. According to the CVE description, rsu_send_async_msg() fails when RSU is disabled in firmware, the channel is freed via stratix10_svc_free_channel(), but the probe path continues and registers svc_normal_to_secure_thread(). That thread later uses the already-freed channel, leading to a kernel NULL pointer dereference and panic. NVD maps the weakness to CWE-476 and lists affected Linux kernel versions as 6.19 through before 6.19.9, plus 7.0-rc1, 7.0-rc2, and 7.0-rc3.
Defensive priority
Medium. The issue does not indicate confidentiality or integrity impact, but it can crash the kernel on affected systems. Priority should be higher for fleets that run Stratix 10 hardware or custom kernels with this driver enabled and may boot with RSU disabled in firmware.
Recommended defensive actions
- Apply the referenced kernel patches from the official Linux stable references.
- Verify whether deployed Stratix 10 systems use the stratix10-rsu driver and whether RSU is disabled in FSBL or firmware.
- Backport the fix into any supported kernel branches that include the affected code path.
- Test boot and service behavior on representative hardware after patching to confirm the driver now exits cleanly when RSU is unavailable.
- Track the affected kernel version window in patch management, especially Linux 6.19 through before 6.19.9 and the listed 7.0 release candidates.
Evidence notes
The CVE description states that when RSU is not enabled in FSBL, rsu_send_async_msg() fails, the channel is freed, but probe continues and registers svc_normal_to_secure_thread(), which later dereferences the invalid channel and panics the kernel. NVD assigns CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H and CWE-476. The supplied source also includes two official kernel patch references, indicating a code-level fix was published.
Official resources
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CVE-2026-43410 CVE record
CVE.org
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CVE-2026-43410 NVD detail
NVD
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Source item URL
nvd_modified
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Mitigation or vendor reference
416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch
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Mitigation or vendor reference
416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch
Publicly disclosed in the CVE record on 2026-05-08T15:16:52.633Z; the supplied NVD record was modified on 2026-05-21T18:14:24.140Z. Not listed as KEV in the supplied enrichment.