VulnerabilityPublished 18 Oct 2026

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

Source GCVE Database

Authoritative record:CVE-2026-98573· High

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

Data as of 26 Oct 2026, 17:16 UTC

Severity

High

Rated by Threat Radar · 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.

ghsa-23rj-wp7f-556g

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

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AI-suggested

A fix has been implemented in the Linux kernel to address this issue by correcting the pull-bound calculation in skb_checksum_setup_ipv6(). Users should apply the official kernel updates that include this patch. Since no vendor advisory or patch links are provided, verify with the Linux kernel maintainers or distribution vendors for the appropriate updated kernel versions.

Description

A vulnerability in the Linux kernel's network stack related to skb_checksum_setup_ipv6() has been resolved. The issue involves an underflow in the pull-bound calculation when parsing IPv6 extension headers, which can lead to a negative delta being passed to skb_copy_bits(), potentially causing an excessively large copy operation. This flaw arises when the skb linear area is larger than MAX_IPV6_HDR_LEN and the parser attempts to access data beyond this area. The fix involves passing the requested length directly to prevent the delta from becoming negative.

Impact

This vulnerability could cause skb_copy_bits() to perform an excessively large copy operation due to an underflow in pull-bound calculation when processing IPv6 extension headers. While the exact impact is not detailed, such behavior could potentially lead to memory corruption or kernel instability. No known exploits in the wild have been reported.

Summary

The vulnerability in the Linux kernel's net subsystem concerns skb_checksum_setup_ipv6() where skb_maybe_pull_tail() subtracts skb_headlen(skb) from an unsigned max argument and passes the result as a signed integer to __pskb_pull_tail() without ensuring max is at least skb_headlen(skb). When parsing IPv6 extension headers with an skb linear area larger than MAX_IPV6_HDR_LEN, this subtraction wraps around, producing a negative delta. This negative delta is then passed to skb_copy_bits(), resulting in a very large copy length. The patch corrects this by passing the requested length itself as the pull bound at the extension-header call sites, preventing the delta from going negative.

References

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