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
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| GNU | Emacs | ≤ 30.2 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | emacs +2 | No fix yet | — |
| Ubuntu 26.04 LTS | xemacs21 +1 | No fix yet | — |
| Ubuntu 24.04 LTS | xemacs21 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | xemacs21 +1 | No fix yet | — |
| Ubuntu 20.04 LTS | xemacs21 +1 | No fix yet | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | xemacs21 +1 | No fix yet | — |
| Ubuntu 16.04 LTS | xemacs21 +1 | No fix yet | — |
| Ubuntu Pro 26.04 LTS | emacs | No fix yet | — |
| Ubuntu Pro 24.04 LTS | emacs | No fix yet | — |
| Ubuntu Pro 22.04 LTS | emacs | No fix yet | — |
| Ubuntu Pro 20.04 LTS | emacs | No fix yet | — |
| Ubuntu Pro 18.04 LTS | emacs25 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | emacs24 | No fix yet | — |
Advisories 1
- WID-SEC-2026-2721 GNU Emacs: Mehrere Schwachstellen BSI CERT-Bund (WID) · Aug 10, 2026