CVE-2026-71392: gnu emacs Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-71392 is a medium (CVSS 5.3) Integer Overflow or Wraparound vulnerability in gnu emacs. EPSS estimates a 0.67% chance of exploitation in the next 30 days, higher than 51.2% of scored vulnerabilities.

Timeline

1. 10-08-2026
   PublishedVulnerability first disclosed.
2. 10-08-2026
   Last modifiedVulnerability information updated.

Description

GNU Emacs for Android is vulnerable to an integer overflow in the sfnt_read_cmap_format_12() function in src/sfnt.c. When processing a crafted TrueType font file, an unguarded addition in the xmalloc allocation call wraps around on 32-bit builds, causing a heap buffer overflow write. 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 results in heap memory corruption that can lead to code execution. This issue was fixed in commit c4e20777c26548722a37b03db93243e83a0d6188

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.