# CVE-2026-68315: sctp: validate stream count in sctp_process_strreset_inreq()

> A remote attacker can cause a kernel crash via integer overflow in SCTP stream reset processing on interfaces with large MTUs.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-68315, DEBIAN-CVE-2026-68315, GHSA-xm4m-qj4q-fpc2, UBUNTU-CVE-2026-68315

## What is CVE-2026-68315?

CVE-2026-68315 is a high-severity vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-190 (Integer Overflow or Wraparound)

## Which versions are affected by CVE-2026-68315?


## How do I fix CVE-2026-68315?

Apply the vendor's patch.

## Is CVE-2026-68315 being exploited?

There is no known exploitation of CVE-2026-68315 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68315 and fix it if it is affected.

What it is: CVE-2026-68315 is a high-severity vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68315 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68315/ (Markdown: https://insights.sbomify.com/CVE-2026-68315/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68315
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68315
- OSV: https://osv.dev/vulnerability/CVE-2026-68315

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68315/
Summaries are generated and may contain mistakes; the official description above is the record.