How severe is CVE-2026-44638?

CVE-2026-44638 has a CVSS 3.x base score of 2.5, rated low severity. It is exploitable over local access with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-44638 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-44638?

CVE-2026-44638 affects Saitoha Libsixel. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-44638?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-44638 have an EU (EUVD) identifier?

Yes. CVE-2026-44638 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30411.

When was CVE-2026-44638 published?

CVE-2026-44638 was published on 2026-05-14 and last updated on 2026-06-17.

CVE-2026-44638

CVE-2026-44638 is a low-severity vulnerability in Saitoha Libsixel with a CVSS 3.x base score of 2.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: Low (CVSS 3.x base score 2.5)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30411
Weakness: CWE-476
Affected product: Saitoha Libsixel
Published: 2026-05-14
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2026-44638?: 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.
How severe is CVE-2026-44638?: CVE-2026-44638 has a CVSS 3.x base score of 2.5, rated low severity. It is exploitable over local access with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-44638 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-44638?: CVE-2026-44638 affects Saitoha Libsixel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-44638?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-44638 have an EU (EUVD) identifier?: Yes. CVE-2026-44638 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30411.
When was CVE-2026-44638 published?: CVE-2026-44638 was published on 2026-05-14 and last updated on 2026-06-17.

References

https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3w

Affected products (1)

cpe:2.3:a:saitoha:libsixel:*:*:*:*:*:*:*:*

More vulnerabilities in Saitoha Libsixel

CVE-2019-19638 — Critical (CVSS 9.8): An issue was discovered in libsixel 1.8.2. There is a heap-based buffer overflow in the function load_pnm at frompnm.c,…
CVE-2019-19637 — Critical (CVSS 9.8): An issue was discovered in libsixel 1.8.2. There is an integer overflow in the function sixel_decode_raw_impl at…
CVE-2019-19636 — Critical (CVSS 9.8): An issue was discovered in libsixel 1.8.2. There is an integer overflow in the function sixel_encode_body at tosixel.c.
CVE-2019-19635 — Critical (CVSS 9.8): An issue was discovered in libsixel 1.8.2. There is a heap-based buffer overflow in the function sixel_decode_raw_impl…
CVE-2022-27046 — High (CVSS 8.8): libsixel 1.8.6 suffers from a Heap Use After Free vulnerability in in libsixel/src/dither.c:388.
CVE-2022-27044 — High (CVSS 8.8): libsixel 1.8.6 is affected by Buffer Overflow in libsixel/src/quant.c:876.

All CVEs affecting Saitoha Libsixel →

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