# CVE-2022-49838: sctp: clear out_curr if all frag chunks of current msg are pruned

Status: published. Published: 2025-05-01. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

sctp: clear out_curr if all frag chunks of current msg are pruned

A crash was reported by Zhen Chen:

  list_del corruption, ffffa035ddf01c18->next is NULL
  WARNING: CPU: 1 PID: 250682 at lib/list_debug.c:49 __list_del_entry_valid+0x59/0xe0
  RIP: 0010:__list_del_entry_valid+0x59/0xe0
  Call Trace:
   sctp_sched_dequeue_common+0x17/0x70 [sctp]
   sctp_sched_fcfs_dequeue+0x37/0x50 [sctp]
   sctp_outq_flush_data+0x85/0x360 [sctp]
   sctp_outq_uncork+0x77/0xa0 [sctp]
   sctp_cmd_interpreter.constprop.0+0x164/0x1450 [sctp]
   sctp_side_effects+0x37/0xe0 [sctp]
   sctp_do_sm+0xd0/0x230 [sctp]
   sctp_primitive_SEND+0x2f/0x40 [sctp]
   sctp_sendmsg_to_asoc+0x3fa/0x5c0 [sctp]
   sctp_sendmsg+0x3d5/0x440 [sctp]
   sock_sendmsg+0x5b/0x70

and in sctp_sched_fcfs_dequeue() it dequeued a chunk from stream
out_curr outq while this outq was empty.

Normally stream->out_curr must be set to NULL once all frag chunks of
current msg are dequeued, as we can see in sctp_sched_dequeue_done().
However, in sctp_prsctp_prune_unsent() as it is not a proper dequeue,
sctp_sched_dequeue_done() is not called to do this.

This patch is to fix it by simply setting out_curr to NULL when the
last frag chunk of current msg is dequeued from out_curr stream in
sctp_prsctp_prune_unsent().

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51; < e27458b18b35caee4b27b37a4a9c503b93cae5cc (affected, git); ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51; < 2ea600b598dd3e061854dd4dd5b4c815397dfcea (affected, git); ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51; < 3eff34e01062ec08fbb45ce2baaaa644550be821 (affected, git); ≥ 5bbbbe32a43199c2b9ea5ea66fab6241c64beb51; < 2f201ae14ae0f91dbf1cffea7bb1e29e81d4d108 (affected, git). Source: CNA: Linux
- Linux / Linux: 4.15 (affected); ≥ 0; < 4.15 (unaffected, semver); ≥ 5.10.156; ≤ 5.10.* (unaffected, semver); ≥ 5.15.81; ≤ 5.15.* (unaffected, semver); ≥ 6.0.10; ≤ 6.0.* (unaffected, semver); ≥ 6.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.21% as of 2026-11-05; percentile 12.00%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/e27458b18b35caee4b27b37a4a9c503b93cae5cc (CNA: Linux)

- https://git.kernel.org/stable/c/2ea600b598dd3e061854dd4dd5b4c815397dfcea (CNA: Linux)

- https://git.kernel.org/stable/c/3eff34e01062ec08fbb45ce2baaaa644550be821 (CNA: Linux)

- https://git.kernel.org/stable/c/2f201ae14ae0f91dbf1cffea7bb1e29e81d4d108 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2022-49838; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2022-49838; retrieved 2026-11-05; source updated Not reported

Revision: 49b38666f807c722d6e3abff06a23e655e2bff56660299082eefd681aa03331c

Canonical: https://y2.dev/cve/CVE-2022-49838

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