CVE-2026-44638— libsixel: NULL pointer dereference
Possible ATT&CK Techniques 1AI
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I. Basic Information for CVE-2026-44638
Vulnerability Information
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Vulnerability Title
libsixel: NULL pointer dereference
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L
Source: NVD (National Vulnerability Database)
Vulnerability Type
空指针解引用
Source: NVD (National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-44638
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- https://github.com/saitoha/libsixel/security/advisories/GHSA-wpx3-h5g8-qr3wx_refsource_CONFIRM
- https://nvd.nist.gov/vuln/detail/CVE-2026-44638
Same Patch Batch · saitoha · 2026-05-14 · 3 CVEs total
| CVE-2026-44636 | 7.4 HIGH | libsixel: integer overflow in encoder |
| CVE-2026-44637 | 7.1 HIGH | libsixel: integer overflow in parser |
IV. Related Vulnerabilities
Same product: libsixel
- CVE-2026-44637
libsixel: integer overflow in parser - CVE-2026-44636
libsixel: integer overflow in encoder - CVE-2026-33023
libsixel: Use-after-free in load_with_gdkpixbuf() - CVE-2026-33021
libsixel: Use-after-free in sixel_encoder_encode_bytes() - CVE-2026-33020
libsixel: Integer Overflow in write_png_to_file() leads to H
Same vendor: saitoha
- CVE-2026-44637
libsixel: integer overflow in parser - CVE-2026-44636
libsixel: integer overflow in encoder - CVE-2026-33023
libsixel: Use-after-free in load_with_gdkpixbuf() - CVE-2026-33021
libsixel: Use-after-free in sixel_encoder_encode_bytes() - CVE-2026-33020
libsixel: Integer Overflow in write_png_to_file() leads to H
Same weakness: CWE-476
- CVE-2026-8723
qs.stringify crashes on null/undefined entries in comma-form - CVE-2026-42409
BIG-IP HTTP/2 vulnerability - CVE-2026-42442
NanaZip: Null-pointer dereference in NanaZip UFS parser when - CVE-2026-34662
Illustrator | NULL Pointer Dereference (CWE-476) - CVE-2026-40413
Windows TCP/IP Denial of Service Vulnerability
V. Comments for CVE-2026-44638
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