Bug 2513474 (CVE-2026-68315) - CVE-2026-68315 kernel: sctp: validate stream count in sctp_process_strreset_inreq()
Summary: CVE-2026-68315 kernel: sctp: validate stream count in sctp_process_strreset_i...
Keywords:
Status: NEW
Alias: CVE-2026-68315
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-10 12:39 UTC by OSIDB Bzimport
Modified: 2026-08-11 08:15 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-08-10 12:39:23 UTC
In the Linux kernel, the following vulnerability has been resolved:

sctp: validate stream count in sctp_process_strreset_inreq()

When processing a RESET_IN_REQUEST from a peer,
sctp_process_strreset_inreq() derives the stream count from the
parameter length but does not check whether the resulting
RESET_OUT_REQUEST would exceed SCTP_MAX_CHUNK_LEN.

The OUT request header (sctp_strreset_outreq, 16 bytes) is 8 bytes
larger than the IN request header (sctp_strreset_inreq, 8 bytes).
Generally, the IP payload is bounded to 65535 bytes, so the stream
list cannot be large enough to trigger the overflow. However, on
interfaces with MTU > 65535 (e.g., loopback with IPv6 jumbograms), a
stream list that fits within the incoming IN parameter can cause a
__u16 overflow in sctp_make_strreset_req() when computing the OUT
request size, leading to an undersized skb allocation and a kernel
BUG:

  net/core/skbuff.c:207         skb_panic
  net/core/skbuff.c:2625        skb_put
  net/sctp/sm_make_chunk.c:1535 sctp_addto_chunk
  net/sctp/sm_make_chunk.c:3695 sctp_make_strreset_req
  net/sctp/stream.c:655         sctp_process_strreset_inreq

The local setsockopt path validates the generated reset request size.
However, for an incoming-only reset, it accounts for the smaller IN
request even though the peer must generate an OUT request with the same
stream list. Such a request cannot be completed successfully by the
peer.

Reject peer IN requests whose corresponding OUT request would exceed
SCTP_MAX_CHUNK_LEN. Also tighten the local check so it does not send an
IN request that would require an oversized OUT request from the peer.

Comment 1 Mauro Matteo Cascella 2026-08-11 08:14:13 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081032-CVE-2026-68315-b0e7@gregkh/T


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