debian/libsixel vulnerabilities

Latest debian/libsixel CVEs

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1. CVE-2026-110601 libsixel before 1.8.7-r1 and 1.9.0 through 1.10.5 Heap Out-of-Bounds Write via GIF

   Published 2026-10-14

   Medium·CVSS 5.8

   libsixel before 1.8.7-r1 and 1.9.0 through 1.10.5 contains a heap out-of-bounds write vulnerability in gif_init_frame() in src/fromgif.c, which never checks the GIF transparent color index against the palette size. Attackers can supply a crafted GIF with a small color table and l...

2. CVE-2026-44637 libsixel: integer overflow in parser

   Published 2026-05-14

   High·CVSS 7.1

   libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, a signed integer overflow in the SIXEL parser's image-buffer doubling loop can lead to an out-of-bounds heap write in sixel_decode_raw_impl. context->pos_x grows by repeat_count on ev...

3. CVE-2026-44636 libsixel: integer overflow in encoder

   Published 2026-05-14

   High·CVSS 7.8

   libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. From to 1.8.7-r1, signed integer overflow in sixel_encode_highcolor's allocation size calculation can lead to a heap buffer overflow. The public sixel_encode entry point validates only that width and h...

4. CVE-2026-44638 libsixel: NULL pointer dereference

   Published 2026-05-14

   Low·CVSS 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 ou...

5. CVE-2026-33023 libsixel: Use-after-free in load_with_gdkpixbuf()

   Published 2026-04-14

   High·CVSS 7.8

   libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. In versions 1.8.7 and prior, when built with the --with-gdk-pixbuf2 option, a use-after-free vulnerability exists in load_with_gdkpixbuf() in loader.c. The cleanup path manually frees the sixel_frame_t...

6. CVE-2026-33021 libsixel: Use-after-free in sixel_encoder_encode_bytes()

   Published 2026-04-14

   High·CVSS 7.3

   libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a use-after-free vulnerability in sixel_encoder_encode_bytes() because sixel_frame_init() stores the caller-owned pixel buffer pointer directly in frame->pixels without...

7. CVE-2026-33020 libsixel: Integer Overflow in write_png_to_file() leads to Heap-based Buffer Overflow

   Published 2026-04-14

   High·CVSS 7.1

   libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain an integer overflow which leads to a heap buffer overflow via sixel_frame_convert_to_rgb888() in frame.c, where allocation size and pointer offset computations for pale...

8. CVE-2026-33019 libsixel: Integer overflow leads to Out-of-bounds Read in img2sixel

   Published 2026-04-14

   High·CVSS 7.1

   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 over...

9. CVE-2026-33018 libsixel: Use-After-Free in load_gif()

   Published 2026-04-14

   High·CVSS 7.0

   libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a Use-After-Free vulnerability via the load_gif() function in fromgif.c, where a single sixel_frame_t object is reused across all frames of an animated GIF and gif_init...

10. CVE-2025-61146 saitoha libsixel until v1.8.7 was discovered to contain a memory leak via the component malloc_stub.c.

    Published 2026-02-23

    Medium·CVSS 4.0

    saitoha libsixel until v1.8.7 was discovered to contain a memory leak via the component malloc_stub.c.

11. CVE-2025-9300 saitoha libsixel img2sixel encoder.c sixel_debug_print_palette stack-based overflow

    Published 2025-08-21

    Medium·CVSS 4.8

    A vulnerability was found in saitoha libsixel up to 1.10.3. Affected by this issue is the function sixel_debug_print_palette of the file src/encoder.c of the component img2sixel. The manipulation results in stack-based buffer overflow. The attack must be initiated from a local po...

12. CVE-2022-29978 There is a floating point exception error in sixel_encoder_do_resize, encoder.c:633 in libsixel img2sixel 1.8.6. Remote attackers could leverage this vulnerability to cause a denial-of-service via a c...

    Published 2022-05-11

    Medium·CVSS 6.5

    There is a floating point exception error in sixel_encoder_do_resize, encoder.c:633 in libsixel img2sixel 1.8.6. Remote attackers could leverage this vulnerability to cause a denial-of-service via a crafted JPEG file.

13. CVE-2022-29977 There is an assertion failure error in stbi__jpeg_huff_decode, stb_image.h:1894 in libsixel img2sixel 1.8.6. Remote attackers could leverage this vulnerability to cause a denial-of-service via a craft...

    Published 2022-05-11

    Medium·CVSS 6.5

    There is an assertion failure error in stbi__jpeg_huff_decode, stb_image.h:1894 in libsixel img2sixel 1.8.6. Remote attackers could leverage this vulnerability to cause a denial-of-service via a crafted JPEG file.

14. CVE-2021-40656 libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.

    Published 2022-04-08

    High·CVSS 8.8

    libsixel before 1.10 is vulnerable to Buffer Overflow in libsixel/src/quant.c:867.

15. CVE-2022-27044 libsixel 1.8.6 is affected by Buffer Overflow in libsixel/src/quant.c:876.

    Published 2022-04-08

    High·CVSS 8.8

    libsixel 1.8.6 is affected by Buffer Overflow in libsixel/src/quant.c:876.

16. CVE-2021-41715 libsixel 1.10.0 is vulnerable to Use after free in libsixel/src/dither.c:379.

    Published 2022-04-08

    High·CVSS 8.8

    libsixel 1.10.0 is vulnerable to Use after free in libsixel/src/dither.c:379.

17. CVE-2022-27046 libsixel 1.8.6 suffers from a Heap Use After Free vulnerability in in libsixel/src/dither.c:388.

    Published 2022-04-08

    High·CVSS 8.8

    libsixel 1.8.6 suffers from a Heap Use After Free vulnerability in in libsixel/src/dither.c:388.

18. CVE-2021-46700 In libsixel 1.8.6, sixel_encoder_output_without_macro (called from sixel_encoder_encode_frame in encoder.c) has a double free.

    Published 2022-02-19

    Medium·CVSS 6.5

    In libsixel 1.8.6, sixel_encoder_output_without_macro (called from sixel_encoder_encode_frame in encoder.c) has a double free.

19. CVE-2021-45340 In Libsixel prior to and including v1.10.3, a NULL pointer dereference in the stb_image.h component of libsixel allows attackers to cause a denial of service (DOS) via a crafted PICT file.

    Published 2022-01-25

    Medium·CVSS 6.5

    In Libsixel prior to and including v1.10.3, a NULL pointer dereference in the stb_image.h component of libsixel allows attackers to cause a denial of service (DOS) via a crafted PICT file.

20. CVE-2020-21548 Libsixel 1.8.3 contains a heap-based buffer overflow in the sixel_encode_highcolor function in tosixel.c.

    Published 2021-09-17

    High·CVSS 8.8

    Libsixel 1.8.3 contains a heap-based buffer overflow in the sixel_encode_highcolor function in tosixel.c.

21. CVE-2020-21547 Libsixel 1.8.2 contains a heap-based buffer overflow in the dither_func_fs function in tosixel.c.

    Published 2021-09-17

    High·CVSS 8.8

    Libsixel 1.8.2 contains a heap-based buffer overflow in the dither_func_fs function in tosixel.c.

22. CVE-2020-21050 Libsixel prior to v1.8.3 contains a stack buffer overflow in the function gif_process_raster at fromgif.c.

    Published 2021-09-14

    Medium·CVSS 6.5

    Libsixel prior to v1.8.3 contains a stack buffer overflow in the function gif_process_raster at fromgif.c.

23. CVE-2020-21049 An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.

    Published 2021-09-14

    Medium·CVSS 6.5

    An invalid read in the stb_image.h component of libsixel prior to v1.8.5 allows attackers to cause a denial of service (DOS) via a crafted PSD file.

24. CVE-2020-21048 An issue in the dither.c component of libsixel prior to v1.8.4 allows attackers to cause a denial of service (DOS) via a crafted PNG file.

    Published 2021-09-14

    Medium·CVSS 6.5

    An issue in the dither.c component of libsixel prior to v1.8.4 allows attackers to cause a denial of service (DOS) via a crafted PNG file.

25. CVE-2020-21677 A heap-based buffer overflow in the sixel_encoder_output_without_macro function in encoder.c of Libsixel 1.8.4 allows attackers to cause a denial of service (DOS) via converting a crafted PNG file int...

    Published 2021-08-10

    Medium·CVSS 6.5

    A heap-based buffer overflow in the sixel_encoder_output_without_macro function in encoder.c of Libsixel 1.8.4 allows attackers to cause a denial of service (DOS) via converting a crafted PNG file into Sixel format.

Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.