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CVE-2026-99165

UnknownEPSS 0.17%

Last modified

CVE-2026-99165 is a vulnerability of currently unknown severity. In the Linux kernel, the following vulnerability has been resolved: sctp: revalidate output stream after association connect wait When message interleaving is enabled, the first send waits for association establishment before building its data chunks. The wait drops the socket lock, and handshake processing can reduce the output stream count to the peer-advertised inbound stream count. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: revalidate output stream after association connect wait When message interleaving is enabled, the first send waits for association establishment before building its data chunks. The wait drops the socket lock, and handshake processing can reduce the output stream count to the peer-advertised inbound stream count. sctp_stream_init() then frees the extension of every removed stream. The sender resumes with the stream that it checked before the wait. If the peer removed that stream, sctp_outq_tail() later dereferences its NULL extension. Fatal-oops policies then panic the host. KASAN: null-ptr-deref in range [0x38-0x3f] RIP: sctp_outq_tail+0x49e/0xaa0 Call Trace: sctp_primitive_SEND sctp_sendmsg_to_asoc sctp_sendmsg A range check alone is insufficient. Stream reconfiguration can grow the output count again while the lock is released without recreating extensions freed by the earlier shrink. The stream can then be in range while its extension remains NULL. The send-buffer wait has the same issue. Factor the range and extension checks into a helper and repeat both after each send-path wait that drops the socket lock. Once the lock is reacquired, the validation remains stable through data creation and queueing. If validation fails after the connect wait, the auto-created association is already established. Return ESRCH so the existing caller path keeps it under state-machine ownership instead of freeing it directly, which would leave protocol, counter and socket state inconsistent.

Metrics

EPSS Probability
0.17%

6.6th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

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

VendorProductVersions
LinuxLinux>= 668c9beb9020d5834ee9e43c208190a07d2b1928, < 26af2969b29cc5eb893a454fee2a36b39521a5bd; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < b925652ba3a3ee11b2617e68de92379144b5b84b; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < 504bdf55438ad4b1ecbfba0f7fe95e1933f7fb66; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < 994694a2d4611d7b76cf05ff401a92b1c0451e1f; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < 84f741b7bb3974e674c9739055826aa040362bba; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < 77a63d1b813b08c4e5a948f5e04fbaca6176aa8f; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < fd56ac95ec31a05b66e8938debfa847f49c0e993; >= 668c9beb9020d5834ee9e43c208190a07d2b1928, < b7ad72414c673ce1fa1f463e807cd4f34f8be9bf
LinuxLinux4.16

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99165?
In the Linux kernel, the following vulnerability has been resolved: sctp: revalidate output stream after association connect wait When message interleaving is enabled, the first send waits for association establishment before building its data chunks. The wait drops the socket lock, and handshake processing can reduce the output stream count to the peer-advertised inbound stream count. sctp_stream_init() then frees the extension of every removed stream. The sender resumes with the stream that it checked before the wait. If the peer removed that stream, sctp_outq_tail() later dereferences its NULL extension. Fatal-oops policies then panic the host. KASAN: null-ptr-deref in range [0x38-0x3f] RIP: sctp_outq_tail+0x49e/0xaa0 Call Trace: sctp_primitive_SEND sctp_sendmsg_to_asoc sctp_sendmsg A range check alone is insufficient. Stream reconfiguration can grow the output count again while the lock is released without recreating extensions freed by the earlier shrink. The stream can then be in range while its extension remains NULL. The send-buffer wait has the same issue. Factor the range and extension checks into a helper and repeat both after each send-path wait that drops the socket lock. Once the lock is reacquired, the validation remains stable through data creation and queueing. If validation fails after the connect wait, the auto-created association is already established. Return ESRCH so the existing caller path keeps it under state-machine ownership instead of freeing it directly, which would leave protocol, counter and socket state inconsistent.
How severe is CVE-2026-99165?
Severity scoring for CVE-2026-99165 is pending analysis. The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-99165?
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.

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Source: NVD / NIST