Bug 2492771 (CVE-2026-53246)

Summary: CVE-2026-53246 kernel: sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Stream Control Transmission Protocol (SCTP) implementation. A remote attacker could exploit this by sending a specially crafted COOKIE_ECHO chunk to a listening SCTP server. The server's failure to properly validate the length of a cached peer INIT chunk within the COOKIE_ECHO payload could lead to out-of-bounds reads and memory corruption. This could result in a denial of service or potentially information disclosure.
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Description OSIDB Bzimport 2026-06-25 10:04:52 UTC 
In the Linux kernel, the following vulnerability has been resolved:

sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing

When a listening SCTP server processes a COOKIE_ECHO chunk, the cached
peer INIT chunk embedded after the cookie is parsed and its parameters
are later walked by sctp_process_init() using sctp_walk_params().

However, the chunk header length of this cached INIT chunk was not
validated against the remaining buffer in the COOKIE_ECHO payload. If
the length field is inflated, the parameter walk can run beyond the
actual received data, leading to out-of-bounds reads and potential
memory corruption during later parameter handling (e.g. STATE_COOKIE
processing and kmemdup() copies).

Add a bounds check in sctp_unpack_cookie() to ensure the cached INIT
chunk length does not exceed the available data in the COOKIE_ECHO
buffer before it is used.
Comment 1 Keith Grant 2026-06-25 23:49:47 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062512-CVE-2026-53246-e748@gregkh/T