CVE-2026-71393: Heap Buffer Overflow in GNU Emacs for Android
GNU Emacs for Android is vulnerable to an integer overflow in sfntreadnametable() in src/sfnt.c. The function computes an allocation size using a 32-bit length value from a TrueType font file without overflow checking. On 32-bit targets, a crafted font causes the calculation to wrap, resulting in an undersized heap allocation. A subsequent read() call writes beyond the buffer, causing a heap buffer overflow. 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 can lead to heap memory corruption and potential code execution.
This issue was fixed in commit d51a4722316efe0960994d371e1859099894d1ca
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
GNU Emacs for Androidto a version that resolves this vulnerability.Patch commit d51a4722316efe0960994d371e1859099894d1ca
Event History
Frequently Asked Questions
What is the severity of CVE-2026-71393?
CVE-2026-71393 has a risk rating of 70, indicating a moderate severity level.
How do I fix CVE-2026-71393?
To fix CVE-2026-71393, update to the latest version of GNU Emacs for Android that addresses the integer overflow vulnerability.
What type of vulnerability is CVE-2026-71393?
CVE-2026-71393 is a heap buffer overflow vulnerability caused by an integer overflow in the sfnt_read_name_table() function.
What systems are affected by CVE-2026-71393?
CVE-2026-71393 affects GNU Emacs for Android on 32-bit targets.
What can an attacker achieve by exploiting CVE-2026-71393?
By exploiting CVE-2026-71393, an attacker can potentially execute arbitrary code via a crafted TrueType font file.