CVE-2026-71391Network attack vector

Heap disclosure via variable-font index off-by-one

Published Aug 10, 2026 · Updated Aug 10, 2026

Off-by-one error in GNU Emacs for Android 30.2 and earlier allows remote attackers to disclose heap data via a crafted variable font. The shared-coordinate checks in sfnt_vary_simple_glyph() and sfnt_vary_compound_glyph() accept an index equal to the table count, so memcpy reads past the heap buffer. Emacs must load the font from email, EWW, or a document face; the resulting disclosure can expose heap contents usable to weaken ASLR.

CVSS severity5.3
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Off-by-one error in GNU Emacs for Android 30.2 and earlier allows remote attackers to disclose heap data via a crafted variable font. The shared-coordinate checks in sfnt_vary_simple_glyph() and sfnt_vary_compound_glyph() accept an index equal to the table count, so memcpy reads past the heap buffer. Emacs must load the font from email, EWW, or a document face; the resulting disclosure can expose heap contents usable to weaken ASLR.

The record

CVE
CVE-2026-71391
Published
Aug 10, 2026
Updated
Aug 10, 2026
Vendor
The GnuPG Project
Product
GNU Emacs
Classifications
CWE-193, T1664
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=30.2 changes=[{"at":"commit 95ab9ef627b212d74d321c5bbb5b56a1be7b9fbe","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The GnuPG Project · GNU Emacsversion=0 <=30.2 changes=[{"at":"commit 95ab9ef627b212d74d321c5bbb5b56a1be7b9fbe","status":"unaffected"}]

Published CVSS scores

5.3CERT.PLCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-193Off-by-one Error
T1664Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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