VulnerabilityPublished 18 Oct 2026Updated 21 Oct 2026

CVE-2026-98493: Linux kernel · net: ipconfig: bound DHCP option construction

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in e47a1958e12abc3a17b5231a4f21c8f1bf662e08 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% 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 e47a1958e12abc3a17b5231a4f21c8f1bf662e08, cbaad2922bd5d4d303055ae9afecc8999e6b40c9, abcba6f080c63e403037ecdffde43170d242376a +2

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 ≥ 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < e47a1958e12abc3a17b5231a4f21c8f1bf662e08	Fixed in e47a1958e12abc3a17b5231a4f21c8f1bf662e08
LinuxLinux	Affected ≥ 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < cbaad2922bd5d4d303055ae9afecc8999e6b40c9	Fixed in cbaad2922bd5d4d303055ae9afecc8999e6b40c9
LinuxLinux	Affected ≥ 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < abcba6f080c63e403037ecdffde43170d242376a	Fixed in abcba6f080c63e403037ecdffde43170d242376a
LinuxLinux	Affected ≥ 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < 38a6a118260ebfc82d0c653194d616bdfbd236ac	Fixed in 38a6a118260ebfc82d0c653194d616bdfbd236ac
LinuxLinux	Affected ≥ 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < 24e79508b237dd2a69bc6fb6ac5cf7f126178307	Fixed in 24e79508b237dd2a69bc6fb6ac5cf7f126178307
LinuxLinux	Affected =2.6.36	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: net: ipconfig: bound DHCP option construction ic_dhcp_init_options() appends the hostname (option 12), vendor-class (option 60) and client-ID (option 61) options into the fixed 312-byte bootp_pkt.exten[] buffer. Only the client-ID branch checked the remaining space; the hostname and vendor-class writes were unbounded. A 64-byte hostname together with the maximum 252-byte dhcpclass= identifier needs 18 + (2 + 64) + (2 + 252) = 338 of the 312 available bytes even before the terminating END marker, so the vendor-class memcpy runs past the end of exten[]. With CONFIG_FORTIFY_SOURCE this is reported as a field-spanning write and, when the kernel is booted with panic_on_warn=1, aborts boot with a panic. Route the optional options through a common helper that makes sure the option, its 2-byte header and the END marker all fit and drops an option that would not. Configurations with short options keep sending exactly the same bytes as before.

References

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