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

> A crafted font file can cause Emacs for Android to use uninitialized heap memory, leading to information disclosure or crashes.

- **Severity:** Medium 5.3 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 10 Aug 2026
- **Updated:** 10 Aug 2026
- **Also known as:** GHSA-jx5g-mm7r-35gq, UBUNTU-CVE-2026-71394

## What is CVE-2026-71394?

CVE-2026-71394 is a medium-severity memory corruption vulnerability in GNU Emacs, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official 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

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-71394?


## How do I fix CVE-2026-71394?

No fix has been published for CVE-2026-71394 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-71394 being exploited?

There is no known exploitation of CVE-2026-71394 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-71394 and fix it if it is affected.

What it is: CVE-2026-71394 is a medium-severity memory corruption vulnerability in GNU Emacs, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-71394 in the wild and no public exploit code.

Affected product: GNU Emacs. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-71394/ (Markdown: https://insights.sbomify.com/CVE-2026-71394/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-71394
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-71394
- OSV: https://osv.dev/vulnerability/CVE-2026-71394

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-71394/
Summaries are generated and may contain mistakes; the official description above is the record.