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CVE-2026-98493

net: ipconfig: bound DHCP option construction PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 before 38a6a118260ebfc82d0c653194d616bdfbd236ac; affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 before abcba6f080c63e403037ecdffde43170d242376a; affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 before 24e79508b237dd2a69bc6fb6ac5cf7f126178307; affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 before cbaad2922bd5d4d303055ae9afecc8999e6b40c9; affected 130c0f47fdf9c533deb1136cad5136f6cb7020f0 before e47a1958e12abc3a17b5231a4f21c8f1bf662e08
Linux / Linuxaffected 2.6.36; unaffected 0 before 2.6.36; unaffected 6.6.160 through 6.6.*; unaffected 6.12.112 through 6.12.*; unaffected 6.18.55 through 6.18.*; unaffected 7.2.9 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References