VulnerabilityPublished 23 Oct 2026

CVE-2026-98983: Linux kernel · unshare: don't drop active namespace references that were never taken

Source GCVE Database

Authoritative record:CVE-2026-98983· Medium

Not known to be exploited · fixed in 56fe03a0c05dba4c5f6a23c391f96de1614a098c : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 56fe03a0c05dba4c5f6a23c391f96de1614a098c, 7.1, 6.19 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 23 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-vc4v-q632-x9g5

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=5.15.209 <5.16 >=6.1.175 <6.2 >=6.6.141 <6.7 >=6.12.91 <6.13 >=6.18.33 <6.19 >=7.0.10 <7.1	Fixed in 56fe03a0c05dba4c5f6a23c391f96de1614a098c 7.1 6.19 6.13 6.7 6.2 5.16 0b6f31a3c0b16066f812e94b52a704174a6f23cd
LinuxLinux	Affected =7.1	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to address this issue by properly handling nsproxy references during unshare operations. Users should update to the fixed kernel version once available. Since this is a kernel-level fix, applying the official kernel update or patch from the Linux distribution vendor is the recommended remediation.

Description

A vulnerability in the Linux kernel's unshare system call was resolved. The issue involved dropping active namespace references that were never taken, leading to reference count inconsistencies. This could cause namespaces the caller lives in to no longer be listed by listns(). The problem occurred when set_cred_ucounts() failed during ksys_unshare(), causing improper reference decrementing. The fix involved properly freeing nsproxy structures that were prepared but never installed.

Impact

The impact is that namespace references can be incorrectly decremented, causing the namespaces the caller lives in to disappear from namespace listings. This could lead to inconsistencies in namespace management within the kernel, potentially affecting processes relying on accurate namespace information. There is no indication of direct exploitation or privilege escalation from the provided data.

References

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