5.5

CVE-2023-53296: sctp: check send stream number after wait_for_sndbuf

Modified
AliasesUBUNTU-CVE-2023-53296DEBIAN-CVE-2023-53296
Published 16-09-2025Last modified 11-05-2026

Vulnerability summary

CVE-2023-53296 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.15%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 3
RHSA-2023:6583RHSA-2023:7077RHSA-2024:0575

Timeline

  1. 16-09-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.15%

Chance of exploitation in the next 30 days

Percentile

4%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.14% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu122 products
  • linuxAll versions (No fix recorded) | < 5.4.0-156.173 | < 5.15.0-79.86
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.4.0-1107.115 | < 5.15.0-1042.47
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < 9346a1a21142357972a6f466ba6275ddc54b04ac | ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < 0443fff49d6352160c200064156c25898bd9f58c | ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < b4b6dfad41aaae9e36e44327b18d5cf4b20dd2ce | ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < 667eb99cf7c15fe5b0ecefe75cf658e20ef20c9f | ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < d2128636b303aa9cf065055402ee6697409a8837 | ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < a615e7270318fa0b98bf1ff38daf6cf52d840312 | ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51, < 2584024b23552c00d95b50255e47bd18d306d31a | 4.15
  • linux_kernel≥ 4.15, < 4.19.281 | ≥ 4.20, < 5.4.241 | ≥ 5.5, < 5.10.178 | ≥ 5.11, < 5.15.107 | ≥ 5.16, < 6.1.24 | ≥ 6.2, < 6.2.11 | 6.3:rc1 | 6.3:rc2 | 6.3:rc3 | 6.3:rc4 | 6.3:rc5
Debian1 product
  • linux< 6.1.25-1

3 vendors · 125 products

References

11 links
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