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
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Affected Vendors & Products
References
History
Mon, 10 Aug 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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 | |
| Title | Off-by-One Error in GNU Emacs for Android | |
| First Time appeared |
Gnu
Gnu emacs |
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| Weaknesses | CWE-193 | |
| CPEs | cpe:2.3:a:gnu:emacs:*:*:android:*:*:*:*:* | |
| Vendors & Products |
Gnu
Gnu emacs |
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| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: CERT-PL
Published:
Updated: 2026-08-10T10:22:17.532Z
Reserved: 2026-08-06T09:25:32.311Z
Link: CVE-2026-71391
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OpenCVE Enrichment
Updated: 2026-08-10T11:30:16Z