VulnerabilityPublished 18 Oct 2026

CVE-2026-98829: Linux kernel · wifi: mac80211: drop oversized fragments to avoid extra_len overflow

Source GCVE Database

Authoritative record:CVE-2026-98829· High

Not known to be exploited · fixed in 9338b2dea74cb0fc80a4c958b68e687610ba2261 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:05 UTC

Severity

High

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 9338b2dea74cb0fc80a4c958b68e687610ba2261, 870b8cb9baa9bd859deceb33ae158011e6ba2360, 5e4f3509793b4db2c0835340224743db680e861f

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-8w97-qwf2-rgh5

What to do

Upgrade Linux kernel to 9338b2dea74cb0fc80a4c958b68e687610ba2261, 870b8cb9baa9bd859deceb33ae158011e6ba2360 or 5e4f3509793b4db2c0835340224743db680e861f.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 69f132236827ce7d4531846cc2b9447dd5620aff, < 9338b2dea74cb0fc80a4c958b68e687610ba2261	Fixed in 9338b2dea74cb0fc80a4c958b68e687610ba2261
LinuxLinux	Affected ≥ 69f132236827ce7d4531846cc2b9447dd5620aff, < 870b8cb9baa9bd859deceb33ae158011e6ba2360	Fixed in 870b8cb9baa9bd859deceb33ae158011e6ba2360
LinuxLinux	Affected ≥ 69f132236827ce7d4531846cc2b9447dd5620aff, < 5e4f3509793b4db2c0835340224743db680e861f	Fixed in 5e4f3509793b4db2c0835340224743db680e861f
LinuxLinux	Affected =4.3	Fixed in–

AI-suggested

A fix is available that adds a check to prevent overflow of the fragment length accumulator by dropping oversized fragments. Users should apply the official Linux kernel patch that implements this check. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation. No other mitigation actions are specified or required.

Description

A vulnerability in the Linux kernel's mac80211 wireless subsystem allows oversized IEEE 802.11 fragments to cause an integer overflow in the fragment payload length accumulator. This overflow leads to insufficient buffer allocation and ultimately triggers a kernel crash in softirq context when processing fragmented frames. The issue arises because the fragment length sum is stored in a 16-bit unsigned integer, which can overflow when large fragments are received. The flaw has been fixed by adding a check to drop frames that would cause overflow without increasing memory footprint.

Impact

Exploitation of this vulnerability can cause a denial of service by crashing the Linux kernel when processing maliciously crafted fragmented IEEE 802.11 frames. This crash occurs in softirq context, potentially disrupting wireless networking functionality and system stability. There is no indication of code execution or privilege escalation from the provided data.

Summary

The vulnerability exists in the ieee80211_rx_h_defragment() function of the Linux kernel's mac80211 subsystem. Fragment payload lengths are accumulated into a 16-bit unsigned integer (entry->extra_len). Since an IEEE 802.11 frame can contain up to 16 fragments, the sum of fragment lengths can exceed 65535 bytes, causing an overflow and wraparound of entry->extra_len. This results in pskb_expand_head() allocating insufficient tailroom or skipping allocation, leading to skb_put() appending data beyond buffer limits and triggering skb_over_panic(), which crashes the kernel in softirq context. The fix involves detecting potential overflow before accumulation and dropping the frame if overflow would occur, avoiding increasing the size of the fragment entry structure.

References

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