Every CVE Search/ Get API key

CVE-2026-44638

libsixel: NULL pointer dereference

2.5 LowFix available

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
High
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.13%Up 0.1 points since May 15, 2026
90%50%10%1%

What each source reports

CVE List Score used 2.5

libsixel: NULL pointer dereference

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Record
CVE-2026-44638
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-476, CWE-690
Updated
2026-11-02
EUVDEUVD-2026-30411 2.5

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Record
EUVD-2026-30411
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
NVD 2.5

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Record
CVE-2026-44638
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-476, CWE-690
Updated
2026-11-02
OSV 2.5

libsixel: NULL pointer dereference

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Record
CVE-2026-44638
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Weakness
CWE-476, CWE-690
Updated
2026-11-05
OSVDEBIAN-CVE-2026-44638 2.5

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Record
DEBIAN-CVE-2026-44638
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVUBUNTU-CVE-2026-44638 2.5

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a wrong NULL check after an allocation call in sixel_decode_raw and sixel_decode causes a NULL pointer dereference whenever the allocation fails. The check tests the address of the output parameter (always non-NULL) instead of the value the malloc returned. On allocation failure, the function continues and writes through a NULL pointer, crashing the process. This is a denial of service against any caller of these public APIs that hits a low-memory condition. This vulnerability is fixed in 1.8.7-r2.

Record
UBUNTU-CVE-2026-44638
CVSS 3.1
2.5 LowCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVopenSUSE-SU-2026:12420-1 No score

libsixel-bash-completion-1.10.5-3.1 on GA media

These are all security issues fixed in the libsixel-bash-completion-1.10.5-3.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:12420-1
Updated
2026-11-05

Affected products

Affected packages

Affected packages
PackageAffectedFixed
libsixel
Debian:12
 All versions, plus listed versions
1.10.3-31.10.5-11:1.8.7-11:1.8.7-21:1.8.7-3
Show 4 moreShow less
1:1.8.7-41:1.8.7-51:1.8.7-61:1.8.7-r2-1
 None known
libsixel
Debian:13
 All versions, plus listed versions
1.10.5-11:1.8.7-11:1.8.7-21:1.8.7-31:1.8.7-41:1.8.7-51:1.8.7-61:1.8.7-r2-1
 None known
libsixel
Debian:14
 before 1:1.8.7-r2-1, plus listed versions
1.10.5-11:1.8.7-11:1.8.7-21:1.8.7-31:1.8.7-41:1.8.7-51:1.8.7-6
1:1.8.7-r2-1
libsixel
Ubuntu:16.04:LTS
 All versions, plus listed versions
1.4.2-11.5.2-2
 None known
libsixel
Ubuntu:18.04:LTS
 All versions, plus listed versions
1.5.2-21.7.3-1
 None known
libsixel
Ubuntu:20.04:LTS
 All versions, plus listed versions
1.8.2-11.8.2-2.1
 None known
libsixel
Ubuntu:22.04:LTS
 All versions, plus listed versions
1.8.6-21.10.3-21.10.3-3
 None known
libsixel
Ubuntu:24.04:LTS
 All versions, plus listed versions
1.10.3-31.10.3-3build1
 None known
libsixel
Ubuntu:25.10
 All versions, plus listed versions
1.10.5-1
 None known
libsixel
Ubuntu:26.10
 All versions, plus listed versions
1.10.5-1build11:1.8.7-r2-1
 None known
libsixel
Ubuntu:26.04:LTS
 All versions, plus listed versions
1.10.5-11.10.5-1build1
 None known
libsixel
openSUSE:Tumbleweed
From an advisory covering 4 CVEs
 before 1.10.5-3.1
1.10.5-3.1

History

History
RecordedChangedSources
affected
affected, aliases, facts, referencesOSV
first indexedCVE List, EUVD, NVD, OSV

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

In short

CVE-2026-44638 is a low vulnerability (CVSS 2.5) in Saitoha Libsixel, published May 14, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. Fixed in libsixel 1:1.8.7-r2-1.

References

Show 4 moreShow less
Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open