VulnerabilityPublished 18 Oct 2026

CVE-2026-98573: Linux kernel · net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in d7f474226809471dc7877435e9c492cc914df0bf : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

Severity

High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in d7f474226809471dc7877435e9c492cc914df0bf, cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962, b2da5ed3d8c75e1b729a21b6d3beaed415e263f6 +5

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.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3, < d7f474226809471dc7877435e9c492cc914df0bf	Fixed in d7f474226809471dc7877435e9c492cc914df0bf
LinuxLinux	Affected ≥ 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3, < cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962	Fixed in cfa643f2ca36c6f913fe1a2ceb12412ebb0fd962
LinuxLinux	Affected ≥ 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3, < b2da5ed3d8c75e1b729a21b6d3beaed415e263f6	Fixed in b2da5ed3d8c75e1b729a21b6d3beaed415e263f6
LinuxLinux	Affected ≥ 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3, < a0ad0473c09d2e947aecac5c82e637ec85924b12	Fixed in a0ad0473c09d2e947aecac5c82e637ec85924b12
LinuxLinux	Affected ≥ 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3, < 718747afa5463d9cc5fd9a09f03b2a492edd9b78	Fixed in 718747afa5463d9cc5fd9a09f03b2a492edd9b78
LinuxLinux	Affected ≥ 1431fb31ecbaba1b5718006128f0f2ed0b94e1c3, < 9c4e432132a97b82edf28fa172c39f743e6bfb26	Fixed in 9c4e432132a97b82edf28fa172c39f743e6bfb26

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available and has been applied in several Linux kernel commits as indicated by the fixedVersions hashes. Users and administrators should update their Linux kernel to a version that includes these fixes to remediate the vulnerability.

Description

A vulnerability in the Linux kernel's IPv6 packet processing was fixed to address a pull-bound underflow in skb_checksum_setup_ipv6(). This flaw occurs when parsing IPv6 extension headers if the skb linear area is larger than MAX_IPV6_HDR_LEN, causing an unsigned subtraction to wrap and become negative, leading to an excessively large copy length in skb_copy_bits().

Impact

This vulnerability could lead to memory corruption due to an integer underflow and subsequent large copy operation during IPv6 packet processing in the Linux kernel. Such corruption might be exploitable to cause denial of service or potentially escalate privileges, though no known exploits in the wild have been reported.

Summary

The Linux kernel contained a vulnerability in the net subsystem related to skbuff handling during IPv6 extension header parsing. Specifically, skb_maybe_pull_tail() subtracts skb_headlen(skb) from an unsigned max argument and passes the result as a signed int to __pskb_pull_tail() without ensuring max is at least skb_headlen(skb). When the linear area of skb exceeds MAX_IPV6_HDR_LEN, this subtraction wraps around, producing a negative delta that is interpreted as a large positive value in skb_copy_bits(), potentially causing memory corruption or other undefined behavior. The fix involves passing the requested length directly as the pull bound at extension-header call sites to prevent negative deltas.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 10:25 UTC

Technical details

References

Community reviews

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