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CVE-2026-64564

sctp: don't free the ASCONF's own transport in DEL-IP processing PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: sctp: don't free the ASCONF's own transport in DEL-IP processing sctp_process_asconf() caches the transport the ASCONF chunk is processed against in asconf->transport (== chunk->transport, set once in sctp_rcv()). For an ASCONF located through its Address Parameter by __sctp_rcv_asconf_lookup(), that cached transport corresponds to the Address Parameter, which need not be the packet's source address. sctp_process_asconf_param() rejects a DEL-IP for the packet source address (ADDIP D8, SCTP_ERROR_DEL_SRC_IP), but nothing protects asconf->transport. A single ASCONF can therefore carry, in order: [Address Parameter L] [DEL-IP L] [DEL-IP 0.0.0.0] where L differs from the source. The DEL-IP for L passes the D8 check and calls sctp_assoc_rm_peer() on the transport that asconf->transport still points at, freeing it (RCU-deferred). The following wildcard DEL-IP then reuses the now-dangling asconf->transport in sctp_assoc_set_primary() and sctp_assoc_del_nonprimary_peers(): set_primary() dereferences the freed transport (->ipaddr, ->state) and plants the dangling pointer into asoc->peer.primary_path / active_path, and del_nonprimary_peers(), keeping only the pointer that is no longer on the list, removes every real transport, leaving the association with a transport_count of 0 and primary_path/active_path pointing at freed memory. Reject a DEL-IP that targets the transport the ASCONF is being processed against, mirroring the existing source-address guard, so the wildcard branch can never reuse a freed transport.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 42e30bf3463cd37d73839376662cb79b4d5c416c before a9ce31be4cb1a5dd82b3e0a1d0c3e7cbdcd31293; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before a63afa1f9b12d5293cbe0b77fd45dc0632533a13; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before 2b324ba3494ae958cba16a453e3e71489b4de7fc; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before fedeb4468987bcaff85fe3061de5ae052d414740; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before 74e8f3e7114f0e26d1b2c4c048044db9fcc27603; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before 85aca407c560aba81b5ce9d3d6cf94c74077d19b; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before d136b29bf91dd8e3161281b87de597b7311d9462; affected 42e30bf3463cd37d73839376662cb79b4d5c416c before 9b2854f86f0b56e9027d68e7a3fc909d1a9b566f
Linux / Linuxaffected 2.6.25; unaffected 0 before 2.6.25; unaffected 5.10.265 through 5.10.*; unaffected 5.15.216 through 5.15.*; unaffected 6.1.183 through 6.1.*; unaffected 6.6.148 through 6.6.*; unaffected 6.12.101 through 6.12.*; unaffected 6.18.42 through 6.18.*; unaffected 7.1.6 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CVE

No English description supplied.

CISA-ADP

No English description supplied.

No references supplied.