CVE-2026-71391
MEDIUM
5,3
Source: [email protected]
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: passive
Confidentiality: N/A
Integrity: N/A
Availability: N/A
Description
AI Translation Available
GNU Emacs for Android contains an off-by-one error in the gvar table parser in src/sfnt.c. The shared-coordinate index boundary check in sfnt_vary_simple_glyph() and sfnt_vary_compound_glyph() uses a strict greater-than comparison instead of greater-than-or-equal, allowing a crafted TrueType variable font to bypass the check and trigger a heap-based out-of-bounds read via memcpy. 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 exposes heap memory contents which can be later used to defeat ASLR.
This issue was fixed in commit 95ab9ef627b212d74d321c5bbb5b56a1be7b9fbe
193
Off-by-one Error
DraftCommon Consequences
Security Scopes Affected:
Availability
Integrity
Confidentiality
Access Control
Potential Impacts:
Dos: Crash, Exit, Or Restart
Dos: Resource Consumption (Cpu)
Dos: Resource Consumption (Memory)
Dos: Instability
Modify Memory
Execute Unauthorized Code Or Commands
Bypass Protection Mechanism
Applicable Platforms
Languages:
C, Not Language-Specific
https://cert.pl/en/posts/2026/08/CVE-2026-71391
https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=95ab9ef627b212d74d321c5b…
https://www.gnu.org/savannah-checkouts/gnu/emacs/emacs.html