CVE-2026-98493: Linux Vulnerability

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.

Metrics

EPSS Probability

0.20%

9.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < e0a221cec0e0ee437680ae0314a4b166509442c5; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < ca811550b9fa87e02845b4a332d194c2304d933f; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < d8016c82acdd7eaa462e1f38a962b15d8c6a650b; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < 38a6a118260ebfc82d0c653194d616bdfbd236ac; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < abcba6f080c63e403037ecdffde43170d242376a; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < 24e79508b237dd2a69bc6fb6ac5cf7f126178307; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < cbaad2922bd5d4d303055ae9afecc8999e6b40c9; >= 130c0f47fdf9c533deb1136cad5136f6cb7020f0, < e47a1958e12abc3a17b5231a4f21c8f1bf662e08
Linux	Linux	2.6.36

References

Timeline

Published: Oct 18, 2026
Last Modified: Oct 30, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-98493?

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.

How severe is CVE-2026-98493?

Severity scoring for CVE-2026-98493 is pending analysis. The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-98493?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →