sctp: check send stream number after wait_for_sndbuf

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: check send stream number after wait_for_sndbuf This patch fixes a corner case where the asoc out stream count may change after wait_for_sndbuf. When the main thread in the client starts a connection, if its out stream count is set to N while the in stream count in the server is set to N - 2, another thread in the client keeps sending the msgs with stream number N - 1, and waits for sndbuf before processing INIT_ACK. However, after processing INIT_ACK, the out stream count in the client is shrunk to N - 2, the same to the in stream count in the server. The crash occurs when the thread waiting for sndbuf is awake and sends the msg in a non-existing stream(N - 1), the call trace is as below: KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f] Call Trace: <TASK> sctp_cmd_send_msg net/sctp/sm_sideeffect.c:1114 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1777 [inline] sctp_side_effects net/sctp/sm_sideeffect.c:1199 [inline] sctp_do_sm+0x197d/0x5310 net/sctp/sm_sideeffect.c:1170 sctp_primitive_SEND+0x9f/0xc0 net/sctp/primitive.c:163 sctp_sendmsg_to_asoc+0x10eb/0x1a30 net/sctp/socket.c:1868 sctp_sendmsg+0x8d4/0x1d90 net/sctp/socket.c:2026 inet_sendmsg+0x9d/0xe0 net/ipv4/af_inet.c:825 sock_sendmsg_nosec net/socket.c:722 [inline] sock_sendmsg+0xde/0x190 net/socket.c:745 The fix is to add an unlikely check for the send stream number after the thread wakes up from the wait_for_sndbuf.

Scores

EPSS (exploitation in 30 days)

0.15% · top 96% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Weakness

• CWE-476 NULL Pointer Dereference (opens in a new tab)All about CWE-476 and its CVEs

Affected products

• Linux · Linux

  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < 9346a1a21142357972a6f466ba6275ddc54b04ac
  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < 0443fff49d6352160c200064156c25898bd9f58c
  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < b4b6dfad41aaae9e36e44327b18d5cf4b20dd2ce
  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < 667eb99cf7c15fe5b0ecefe75cf658e20ef20c9f
  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < d2128636b303aa9cf065055402ee6697409a8837
  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < a615e7270318fa0b98bf1ff38daf6cf52d840312
  • affected 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51 – < 2584024b23552c00d95b50255e47bd18d306d31a

• Linux · Linux

  • affected 4.15
  • unaffected < 4.15
  • unaffected 4.19.281 – ≤ 4.19.*
  • unaffected 5.4.241 – ≤ 5.4.*
  • unaffected 5.10.178 – ≤ 5.10.*
  • unaffected 5.15.107 – ≤ 5.15.*
  • unaffected 6.1.24 – ≤ 6.1.*
  • unaffected 6.2.11 – ≤ 6.2.*
  • unaffected 6.3 – ≤ *

References (7)

• https://git.kernel.org/stable/c/9346a1a21142357972a6f466ba6275ddc54b04ac (opens in a new tab)
• https://git.kernel.org/stable/c/0443fff49d6352160c200064156c25898bd9f58c (opens in a new tab)
• https://git.kernel.org/stable/c/b4b6dfad41aaae9e36e44327b18d5cf4b20dd2ce (opens in a new tab)
• https://git.kernel.org/stable/c/667eb99cf7c15fe5b0ecefe75cf658e20ef20c9f (opens in a new tab)
• https://git.kernel.org/stable/c/d2128636b303aa9cf065055402ee6697409a8837 (opens in a new tab)
• https://git.kernel.org/stable/c/a615e7270318fa0b98bf1ff38daf6cf52d840312 (opens in a new tab)
• https://git.kernel.org/stable/c/2584024b23552c00d95b50255e47bd18d306d31a (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2023-53296](https://trackcve.app/badge/CVE-2023-53296.svg)](https://trackcve.app/cve/CVE-2023-53296)

Record last updated 11 May 2026, 19:42 UTC.