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CVE-2026-98596

Microsoft — ipv6: Fix dst leak for uncached routes.

Microsoft · Not classified by connected sources

Patch Tuesday
0

EVRS 0 of 100 Informational

Monitor

Rank 2,845 of 2,960 tracked

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Why it scores 0

Evidence available: 2 of 8 signals

No strong exploitation, disclosure, or severity signal is available for this CVE yet.

  • CISA KEVDid not apply
  • RansomwareNo data
  • Vendor exploitationNo data
  • EPSSDid not apply
  • Microsoft Exploitability IndexNo data
  • Pre-patch disclosureNo data
  • KEV recencyNo data
  • CVSSNo data

The band answers “how soon”, not “how bad”. No data for: Ransomware, Vendor exploitation, Microsoft Exploitability Index, Pre-patch disclosure, KEV recency, CVSS. Why some signals show no data

Fix

No fixed version identified yet

Affected versions

Not identified by the connected sources

Remediation

NVD lists one or more references for this CVE that aren't tagged as a patch or vendor advisory. Review them directly to confirm patch availability and applicability before making a remediation decision.

Evidence

Each value with its source
MeasureValueSource
CVSS base scoreHow severe the flaw is in itself. It does not say how likely an attack is. Not publishedNVD and the CVE record were checked and hold no score. NVD
FIRST EPSSFIRST's estimate of the chance this is exploited in the next 30 days, and how that ranks against all CVEs. 0.002 (9.3rd pctl) FIRST EPSS
Actively exploitedWhether a source of record has confirmed attacks using it in the wild. Not confirmed Patch Tuesday
Public exploit moduleA module existing is not the same as active exploitation. None known Metasploit
EUVD cross-referenceENISA's record: CVSS 0.0, assigned by Linux. Listed ENISA EUVD

Description

NVD

In the Linux kernel, the following vulnerability has been resolved: ipv6: Fix dst leak for uncached routes. ip6_route_output_flags(), ip6_rt_put_flags(), and ip6_dst_check() detect an uncached route by list_empty(&rt->dst.rt_uncached), which replaced the static DST_NOCACHE flag check in commit a4c2fd7f7891 ("net: remove DST_NOCACHE flag"). When a device is unregistered, rt6_uncached_list_flush_dev() unlinks uncached routes tied to the device from rt6_uncached_list. Previously, they were moved to another list with list_move() (__list_del_entry() + list_add()), and since commit 98aa546af5e4 ("inet: remove (struct uncached_list)->quarantine"), the routes are just unlinked with list_del_init(). If list_del_init() runs concurrently, list_empty() evaluates to true; ip6_route_output_flags() calls dst_hold_safe() incorrectly and ip6_rt_put_flags() skips ip6_rt_put(), leaking dst, and thus dev tied via rt->from as well. The same race is partially fixed by commit 9a6f0c4d5796 ("dst: fix races in rt6_uncached_list_del() and rt_del_uncached_list()"). Let's check rt6->dst.rt_uncached_list instead. Note that IPv4 does not have the same issue.