VulnerabilityPublished 25 Sep 2026Updated 30 Oct 2026

CVE-2026-97597: Linux kernel · ipv6: flowlabel: cap duplicate leases per socket

Source GCVE Database

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Authoritative record:CVE-2026-97597· Medium

Not known to be exploited · fixed in 467467bf4209f9f8add0c648bae763f92a0224c3 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 17:33 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in 467467bf4209f9f8add0c648bae763f92a0224c3, 0159f716d8adbe85951cdf008d0afe27d874eaa6, 42abef116bb2265eeccae55a0dc91a9f1546f74c +3

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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-7x5f-23mf-qfp3

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 467467bf4209f9f8add0c648bae763f92a0224c3	Fixed in 467467bf4209f9f8add0c648bae763f92a0224c3
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 0159f716d8adbe85951cdf008d0afe27d874eaa6	Fixed in 0159f716d8adbe85951cdf008d0afe27d874eaa6
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 42abef116bb2265eeccae55a0dc91a9f1546f74c	Fixed in 42abef116bb2265eeccae55a0dc91a9f1546f74c
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 8d6cd188508513503805c156165de38e4e4a8615	Fixed in 8d6cd188508513503805c156165de38e4e4a8615
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 6d917992c22b6029fc2dc1bd464b7f6709357161	Fixed in 6d917992c22b6029fc2dc1bd464b7f6709357161
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 2f1a6dd5c80ceb902f50449efe899f29cd7918e3	Fixed in 2f1a6dd5c80ceb902f50449efe899f29cd7918e3

AI-suggested

A fix has been implemented that enforces a maximum number of leases per socket and requires CAP_NET_ADMIN capability to exceed this limit. Users should apply the official Linux kernel update that includes this patch. Until patched, monitoring for unusual socket lease growth may help detect exploitation attempts.

Description

CVE-2026-97597 is a vulnerability in the Linux kernel's IPv6 flowlabel handling where repeated GET requests can cause unbounded growth of a socket's lease list. This occurs because the recheck path links additional leases without proper admission checks. The issue is mitigated by limiting the number of leases per socket and enforcing capability checks to prevent unprivileged users from bypassing restrictions.

Impact

The vulnerability could allow unprivileged users to cause resource exhaustion on a socket by creating an unlimited number of leases, potentially leading to denial of service conditions. The fix prevents unprivileged users from bypassing limits via user namespaces, reducing the risk of host memory exhaustion.

Summary

The vulnerability in the Linux kernel's ipv6_flowlabel_get() function allows unbounded growth of a socket's lease list due to missing admission checks on the recheck path for compatible existing flowlabels. This can be exploited by repeated GET requests for a shareable label. The fix involves capping the number of leases per socket to FL_MAX_PER_SOCK, rejecting new unprivileged leases once the limit is reached, and using capable(CAP_NET_ADMIN) to prevent privilege bypass via user namespaces. The admission check is performed before updating linger and expires to avoid refreshing shared labels on rejected requests.

References

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