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CVE-2026-71394

Heap Use of Uninitialized Memory in GNU Emacs for Android

5.3 Medium

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets.

This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Passive

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.45%Up 0.2 points since Aug 11, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

Heap Use of Uninitialized Memory in GNU Emacs for Android

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets.

This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Record
CVE-2026-71394
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N
Weakness
CWE-1284
Updated
2026-11-02
EUVDEUVD-2026-55257 5.3

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets.

This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Record
EUVD-2026-55257
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-jx5g-mm7r-35gq 5.3

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory()...

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets.

This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Record
GHSA-jx5g-mm7r-35gq
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness
CWE-1284
Updated
2026-11-02
NVD 5.3

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets.

This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Record
CVE-2026-71394
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness
CWE-1284
Updated
2026-11-02
OSVDEBIAN-CVE-2026-71394 5.3

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets. This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Record
DEBIAN-CVE-2026-71394
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated
2026-11-02
OSVUBUNTU-CVE-2026-71394 5.3

GNU Emacs for Android improperly validates the table header input in sfnt_read_table_directory() in src/sfnt.c. Due to an incorrect comparison variable in the read-length check, a crafted font file that claims to contain more table directory entries than actually present causes the parser to return a struct with uninitialized heap memory in the table directory entries. 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 leads to the use of uninitialized heap data in subsequent table lookups, potentially resulting in information disclosure, crashes, or arbitrary memory access on 32-bit targets. This issue is fixed after commit 7621ee1d01229d50e5c0cddea6bf0b01095a62cf

Record
UBUNTU-CVE-2026-71394
CVSS 4.0
5.3 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:L/SI:L/SA:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
emacs24
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
24.5+1-1ubuntu224.5+1-1ubuntu424.5+1-1ubuntu524.5+1-1ubuntu624.5+1-1ubuntu7
Show 6 moreShow less
24.5+1-6ubuntu124.5+1-6ubuntu1.124.5+1-6ubuntu1.1+esm124.5+1-6ubuntu1.1+esm224.5+1-6ubuntu1.1+esm324.5+1-6ubuntu1.1+esm4
None known
xemacs21
Ubuntu:16.04:LTS
All versions, plus listed versions
21.4.22-4ubuntu321.4.22-14ubuntu1
None known
xemacs21-packages
Ubuntu:16.04:LTS
All versions, plus listed versions
2009.02.17.dfsg.2-2
None known
emacs25
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
25.2+1-625.2+1-6ubuntu0.1~esm2
None known
xemacs21
Ubuntu:18.04:LTS
All versions, plus listed versions
21.4.24-4ubuntu121.4.24-5ubuntu1
None known
xemacs21-packages
Ubuntu:18.04:LTS
All versions, plus listed versions
2009.02.17.dfsg.2-4
None known
emacs
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
1:26.3+1-1ubuntu11:26.3+1-1ubuntu21:26.3+1-1ubuntu2+esm11:26.3+1-1ubuntu2+esm2
None known
xemacs21
Ubuntu:20.04:LTS
All versions, plus listed versions
21.4.24-8build121.4.24-9
None known
xemacs21-packages
Ubuntu:20.04:LTS
All versions, plus listed versions
2009.02.17.dfsg.2-42009.02.17.dfsg.2-5
None known
xemacs21
Ubuntu:22.04:LTS
All versions, plus listed versions
21.4.24-9ubuntu2
None known
Show 11 moreShow less
Affected packages
PackageAffectedFixed
xemacs21-packages
Ubuntu:22.04:LTS
All versions, plus listed versions
2009.02.17.dfsg.2-5
None known
emacs
Ubuntu:Pro:22.04:LTS
All versions, plus listed versions
1:27.1+1-3ubuntu31:27.1+1-3ubuntu51:27.1+1-3ubuntu5.11:27.1+1-3ubuntu5.21:27.1+1-3ubuntu5.2+esm1
None known
xemacs21
Ubuntu:24.04:LTS
All versions, plus listed versions
21.4.24-1221.4.24-12build221.4.24-12build3
None known
xemacs21-packages
Ubuntu:24.04:LTS
All versions, plus listed versions
2009.02.17.dfsg.3-22009.02.17.dfsg.3-3
None known
emacs
Ubuntu:Pro:24.04:LTS
All versions, plus listed versions
1:29.1+1-5ubuntu11:29.2+1-1ubuntu11:29.2+1-2ubuntu41:29.3+1-1ubuntu21:29.3+1-1ubuntu2+esm11:29.3+1-1ubuntu2+esm31:29.3+1-1ubuntu2+esm4
None known
emacs
Ubuntu:26.10
All versions, plus listed versions
1:30.2+1-2ubuntu11:30.2+1-6ubuntu11:30.2+1-11ubuntu1
None known
xemacs21
Ubuntu:26.10
All versions, plus listed versions
21.4.24-12build3
None known
xemacs21-packages
Ubuntu:26.10
All versions, plus listed versions
2009.02.17.dfsg.3-3build1
None known
xemacs21
Ubuntu:26.04:LTS
All versions, plus listed versions
21.4.24-12build3
None known
xemacs21-packages
Ubuntu:26.04:LTS
All versions, plus listed versions
2009.02.17.dfsg.3-32009.02.17.dfsg.3-3build1
None known
emacs
Ubuntu:Pro:26.04:LTS
All versions, plus listed versions
1:30.1+1-9ubuntu11:30.2+1-1ubuntu21:30.2+1-2ubuntu11:30.2+1-2ubuntu1+esm1
None known

History

History
RecordedChangedSources
affected
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-71394 is a medium vulnerability (CVSS 5.3) in Gnu Emacs, published August 10, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.45%, the 38th percentile. No source names a fixed version.

References

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