VulnerabilityPublished 18 Oct 2026

CVE-2026-98595: Linux kernel · udp: remove a disconnected socket from the 4-tuple hash table

Source GCVE Database

Authoritative record:CVE-2026-98595· Medium

Not known to be exploited · fixed in d1b5fd969cc53f29d02b82b05a45135de4a6087a : 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: 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d1b5fd969cc53f29d02b82b05a45135de4a6087a, c21daf37d5ce9a4e234b7c42238ac1e6041e28e4, 9e95b1a94c9c49b4ba722251bbca2759b9c51737

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-mg64-mpw7-gmp2

What to do

Upgrade Linux kernel to d1b5fd969cc53f29d02b82b05a45135de4a6087a, c21daf37d5ce9a4e234b7c42238ac1e6041e28e4 or 9e95b1a94c9c49b4ba722251bbca2759b9c51737.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 78c91ae2c6deb5d236a5a93ff2995cdd05514380, < d1b5fd969cc53f29d02b82b05a45135de4a6087a	Fixed in d1b5fd969cc53f29d02b82b05a45135de4a6087a
LinuxLinux	Affected ≥ 78c91ae2c6deb5d236a5a93ff2995cdd05514380, < c21daf37d5ce9a4e234b7c42238ac1e6041e28e4	Fixed in c21daf37d5ce9a4e234b7c42238ac1e6041e28e4
LinuxLinux	Affected ≥ 78c91ae2c6deb5d236a5a93ff2995cdd05514380, < 9e95b1a94c9c49b4ba722251bbca2759b9c51737	Fixed in 9e95b1a94c9c49b4ba722251bbca2759b9c51737
LinuxLinux	Affected =6.13	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel to remove disconnected UDP sockets from the 4-tuple hash table before disconnection completes. Users should update to a kernel version that includes commit 6996a2d2d0a6 or later, which contains this fix. No other mitigation actions are indicated or necessary.

Description

A vulnerability in the Linux kernel's UDP socket handling was resolved, where a disconnected UDP socket bound to a specific address and port remained in the 4-tuple hash table. This stale entry caused the kernel to continue processing packets through the 4-tuple lookup unnecessarily. The issue affected both IPv4 and IPv6 sockets, with a related but separate IPv6 defect not addressed here. The fix involves removing the socket entry from the hash table before disconnection completes, preventing stale entries and potential lookup inefficiencies.

Impact

The vulnerability results in stale UDP socket entries persisting in the kernel's 4-tuple hash table after socket disconnection. This causes unnecessary packet processing overhead as packets continue to be routed through the 4-tuple lookup. On IPv6, it may also lead to incorrect packet matching due to stale address data, though that specific defect is not addressed by this fix. There is no indication of direct security compromise or exploitation in the provided data.

References

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