Medium severity · published Aug 10, 2026
CVE-2026-71391
Off-by-One Error in GNU Emacs for Android
5.3
CVSS
0.5%
EPSS
No
On KEV
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
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EM
Emacs · GNU
through 30.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-71391
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-71391
cert.pl
https://cert.pl/en/posts/2026/08/CVE-2026-71391
git.savannah.gnu.org
https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=95ab9ef627b212d74d321c5bbb5b56a1be7b9fbe
www.gnu.org
https://www.gnu.org/savannah-checkouts/gnu/emacs/emacs.html
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