VulnerabilityPublished 18 Oct 2026

CVE-2026-98596: Linux kernel · ipv6: Fix dst leak for uncached routes.

Source GCVE Database

Authoritative record:CVE-2026-98596· Medium

Not known to be exploited · fixed in f9722746df13a8a29103c847ef56b02c11ce0963 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f9722746df13a8a29103c847ef56b02c11ce0963, ed902d5546fb9c142b3216d8eec914fa1bc0aa80, be31fe6333f534155e6b408f1ef6d77974bb41aa +1

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-gvvq-54cj-7xg4

What to do

Upgrade Linux kernel to f9722746df13a8a29103c847ef56b02c11ce0963, ed902d5546fb9c142b3216d8eec914fa1bc0aa80, be31fe6333f534155e6b408f1ef6d77974bb41aa or 5045aa25f3790dcdb158a58ac60ccf8da42959aa.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 98aa546af5e4f180439c82da403cc77926d3953b, < f9722746df13a8a29103c847ef56b02c11ce0963	Fixed in f9722746df13a8a29103c847ef56b02c11ce0963
LinuxLinux	Affected ≥ 98aa546af5e4f180439c82da403cc77926d3953b, < ed902d5546fb9c142b3216d8eec914fa1bc0aa80	Fixed in ed902d5546fb9c142b3216d8eec914fa1bc0aa80
LinuxLinux	Affected ≥ 98aa546af5e4f180439c82da403cc77926d3953b, < be31fe6333f534155e6b408f1ef6d77974bb41aa	Fixed in be31fe6333f534155e6b408f1ef6d77974bb41aa
LinuxLinux	Affected ≥ 98aa546af5e4f180439c82da403cc77926d3953b, < 5045aa25f3790dcdb158a58ac60ccf8da42959aa	Fixed in 5045aa25f3790dcdb158a58ac60ccf8da42959aa
LinuxLinux	Affected =6.11	Fixed in–

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by modifying the detection of uncached routes and correcting the race condition in list handling. Users should apply the official kernel updates that include this fix. Since this is a kernel-level issue, upgrading to a patched kernel version is the recommended remediation. No alternative mitigations or workarounds are described.

Description

A vulnerability in the Linux kernel's IPv6 routing code causes a memory leak of destination cache (dst) objects for uncached routes due to a race condition in list handling when devices are unregistered. This flaw can lead to resource leaks tied to network devices. IPv4 is not affected by this issue. The vulnerability has been resolved by changing the detection method for uncached routes and fixing the race condition in list operations.

Impact

The vulnerability causes a memory leak of destination cache objects and associated network device references in the IPv6 routing subsystem of the Linux kernel. This leak occurs due to a race condition during device unregistration and can lead to resource exhaustion over time. There is no indication of direct code execution or privilege escalation from the provided data. IPv4 routing is unaffected.

Summary

The Linux kernel's IPv6 routing functions ip6_route_output_flags(), ip6_rt_put_flags(), and ip6_dst_check() detect uncached routes by checking if the list rt->dst.rt_uncached is empty, replacing a previous static flag check. When a network device is unregistered, the function rt6_uncached_list_flush_dev() unlinks uncached routes tied to that device from the rt6_uncached_list. Previously, routes were moved between lists, but since a commit removing the quarantine list, routes are unlinked with list_del_init(). If list_del_init() runs concurrently, list_empty() may incorrectly evaluate to true, causing ip6_route_output_flags() to call dst_hold_safe() incorrectly and ip6_rt_put_flags() to skip ip6_rt_put(), resulting in a leak of dst objects and associated devices. A partial fix was made in a prior commit addressing races in rt6_uncached_list_del() and rt_del_uncached_list(). The current fix involves checking rt6->dst.rt_uncached_list directly to avoid the race. IPv4 routing code does not have this issue.

References

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