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CVE-2026-33019

Saitoha Libsixel out-of-bounds read

7.1 HIGHPublic exploitEPSS 0.21%
  1. Published14 Apr 2026

Description

libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain an integer overflow leading to an out-of-bounds heap read in the --crop option handling of img2sixel, where positive coordinates up to INT_MAX are accepted without overflow-safe bounds checking. In sixel_encoder_do_clip(), the expression clip_w + clip_x overflows to a large negative value when clip_x is INT_MAX, causing the bounds guard to be skipped entirely, and the unclamped coordinate is passed through sixel_frame_clip() to clip(), which computes a source pointer far beyond the image buffer and passes it to memmove(). An attacker supplying a specially crafted crop argument with any valid image can trigger an out-of-bounds read in the heap, resulting in a reliable crash and potential information disclosure. This issue has been fixed in version 1.8.7-r1.

CVSS 3.1 breakdown

Attack vectorLocal
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Affected products

Saitoha Libsixel< 1.8.7-r1

Remediation

Fixed in
Saitoha Libsixel≥ 1.8.7-r1

References

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Frequently asked

Is CVE-2026-33019 being actively exploited?

CVE-2026-33019 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.21%.

How severe is CVE-2026-33019?

CVE-2026-33019 has a CVSS 3.1 base score of 7.1, rated high. EPSS estimates a 0.21% probability of exploitation.

Which products are affected by CVE-2026-33019?

Affected products include Saitoha Libsixel.

How do I fix CVE-2026-33019?

Upgrade affected software to a fixed version, for example Saitoha Libsixel 1.8.7-r1 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-33019 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.