VulnerabilityPublished 23 Oct 2026

CVE-2026-99057: Linux kernel · xen/netfront: don't leak the skb when xennet_fill_frags() fails

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in 99011a11c97340ef7290df7dc199305c73fab2f2 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 99011a11c97340ef7290df7dc199305c73fab2f2, 086944c1c2cbb683543bc3ff08637847b03c8009, 5051df031144753d3e18862514969146b601d089 +6

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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=4.4.159 <4.5 >=4.9.130 <4.10 >=4.14.73 <4.15 >=4.18.11 <4.19	Fixed in 99011a11c97340ef7290df7dc199305c73fab2f2 086944c1c2cbb683543bc3ff08637847b03c8009 5051df031144753d3e18862514969146b601d089 93ccaf1c26e2133396173b76a071e59024daa622 84e3ea6502b5f14ce8d499d0b6e0e38386274cf0 4.19 4.15 4.10 4.5
LinuxLinux	Affected =4.19	Fixed in–

AI-suggested

This vulnerability has been fixed in Linux kernel versions 4.5, 4.10, 4.15, and 4.19 and their corresponding commits. Users and administrators should upgrade to these fixed versions or later to remediate the issue. No additional mitigation is required once the system is updated.

Description

A vulnerability in the Linux kernel's xen/netfront driver causes a memory leak when the function xennet_fill_frags() fails due to response chains exceeding the skb's fragment capacity. The skb buffer is not freed properly, leading to resource leakage. This issue affects multiple Linux kernel versions and has been fixed in later releases.

Impact

The vulnerability causes a memory leak in the Linux kernel's xen/netfront network driver. Over time, repeated triggering of this condition can exhaust kernel memory resources, potentially degrading system performance or stability. There is no indication of code execution or privilege escalation from this flaw.

Summary

The Linux kernel xen/netfront driver has a vulnerability where, if xennet_fill_frags() encounters more response slots than the skb's fragment list can hold, it returns an error and the error handling path fails to free the skb buffer. This results in a memory leak of the skb and its associated pages. The fix involves reinserting the skb back onto the temporary queue before error handling, ensuring proper cleanup similar to the handling of xennet_set_skb_gso() failures.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 09:59 UTC

Technical details

References

Community reviews

Related threats