Off-by-One Error in GNU Emacs for Android
CVE-2026-71391

5.3MEDIUM

Key Information:

Vendor

Gnu
Status
Emacs
Vendor
CVE Published:
10 August 2026

What is CVE-2026-71391?

GNU Emacs for Android contains a vulnerability caused by an off-by-one error in the gvar table parser, specifically in the src/sfnt.c file. The improper boundary check in the functions sfnt_vary_simple_glyph() and sfnt_vary_compound_glyph() allows attackers to exploit this oversight. By sending a crafted TrueType variable font file, potentially through malicious emails or documents, an attacker can manipulate Emacs into processing the file. This could lead to unauthorized access to sensitive heap memory data, posing significant security risks. The issue was addressed in a recent commit to ensure safer memory handling.

Affected Version(s)

Emacs Android 0 <= 30.2

References

https://cert.pl/en/posts/2026/08/CVE-2026-71391
third-party-advisory
https://www.gnu.org/savannah-checkouts/gnu/emacs/emacs.html
product
https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=95...

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
Unknown

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Michał Majchrowicz (AFINE Team)
Marcin Wyczechowski (AFINE Team)
.