CVE-2026-44638Public exploit

Process crash via unchecked palette allocation failure

Published May 14, 2026 · Updated May 14, 2026

NULL pointer dereference in libsixel 1.0.0 through 1.8.7-r1 allows local users to crash a calling process during SIXEL decoding. The sixel_decode_raw and sixel_decode functions test the palette output-parameter address instead of the allocation result, then write through the returned NULL pointer. Exploitation requires user-supplied SIXEL input plus allocation failure from memory pressure or a failing custom allocator, and the consequence is limited to the calling process crashing.

CVSS severity2.5
Low
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in libsixel 1.0.0 through 1.8.7-r1 allows local users to crash a calling process during SIXEL decoding. The sixel_decode_raw and sixel_decode functions test the palette output-parameter address instead of the allocation result, then write through the returned NULL pointer. Exploitation requires user-supplied SIXEL input plus allocation failure from memory pressure or a failing custom allocator, and the consequence is limited to the calling process crashing.

The record

CVE
CVE-2026-44638
Published
May 14, 2026
Updated
May 14, 2026
Vendor
saitoha
Product
libsixel
Classifications
CWE-690, CWE-476, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 14, 2026CVE publishedPublication date reported by the CVE source.
  2. May 14, 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=>= 1.0.0, < 1.8.7-r2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

saitoha · libsixelversion=>= 1.0.0, < 1.8.7-r2

Published CVSS scores

2.5NIST NVDCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
2.5GitHub, Inc.CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-690Unchecked Return Value to NULL Pointer Dereference
CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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