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PatchSiren cyber security CVE debrief

CVE-2026-64580 Linux CVE debrief

The Linux kernel's xfrm6_fill_dst function has a vulnerability that can lead to a double netdev_put issue. This occurs when the in6_dev_get(dev) function returns NULL, causing xfrm6_fill_dst() to release the device reference with netdev_put() but leave xdst->u.dst.dev set. Later, dst_destroy() calls netdev_put(dst->dev) again, resulting in the same net_device reference being released twice and underflowing its refcount. The fix involves clearing xdst->u.dst.dev after the netdev_put(), similar to how the XFRM device-offload paths xfrm_dev_state_add() and xfrm_dev_policy_add() in net/xfrm/xfrm_device.c handle it. Linux kernel maintainers, users, and administrators should be aware of this vulnerability and take steps to verify and apply the fix. They should review Linux kernel configurations to prevent similar issues and monitor Linux kernel updates for related patches. Additionally, they should consider implementing compensating controls for exposed systems and tracking exceptions and retesting remediated assets.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-08-05
Original CVE updated
2026-08-05
Advisory published
2026-08-05
Advisory updated
2026-08-05

Who should care

Linux kernel maintainers, users, and administrators should be aware of this vulnerability and take steps to verify and apply the fix. They should review Linux kernel configurations to prevent similar issues and monitor Linux kernel updates for related patches. Additionally, they should consider implementing compensating controls for exposed systems and tracking exceptions and retesting remediated assets.

Technical summary

The Linux kernel's xfrm6_fill_dst function has a vulnerability that can lead to a double netdev_put issue. The fix involves clearing xdst->u.dst.dev after the netdev_put(). This vulnerability affects Linux kernel maintainers and users, who should prioritize verifying and applying the fix to prevent potential double netdev_put issues. The vulnerability is related to the xfrm6_fill_dst function, which is part of the Linux kernel's IPsec implementation.

Defensive priority

Linux kernel maintainers and users should prioritize verifying and applying the fix to prevent potential double netdev_put issues.

Recommended defensive actions

  • Verify and apply the fix to the Linux kernel
  • Review and update Linux kernel configurations to prevent similar issues
  • Monitor Linux kernel updates for related patches
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE description indicates a vulnerability in the Linux kernel's xfrm6_fill_dst function, which can lead to a double netdev_put issue. The fix involves clearing xdst->u.dst.dev after the netdev_put(). To verify, defenders should review the Linux kernel's xfrm6_fill_dst function implementation and check for the presence of the fix. Additionally, they should monitor Linux kernel updates for related patches and review compensating controls for exposed systems.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-08-05T08:16:38.027Z and has not been modified since then.