Amazon Linux 2027 Preview Security Advisory: ALAS2027-2026-268
Advisory Released Date: 2026-11-02
Advisory Updated Date: 2026-11-02
FAQs regarding Amazon Linux ALAS/CVE Severity
Package updates are available for Amazon Linux 2027 that fix the following vulnerabilities:
CVE-2026-96778:
Pillow is a Python imaging library. From 9.4.0 until 13.0.0, ImagingJpegEncode() in src/libImaging/JpegEncode.c can call jpeg_write_marker() for a JPEG COM comment when an ICC profile has exactly filled the 65536-byte encoder buffer. libjpeg writes one byte before checking the exhausted free_in_buffer counter, which then wraps and permits the attacker-controlled comment and subsequent compressed image data to overwrite adjacent heap memory. Re-saving an untrusted image as JPEG while preserving its ICC profile and forwarded comment can crash the process and may enable code execution in suitable runtime and heap layouts. This issue is fixed in version 13.0.0.
CVE-2026-96643:
Pillow is a Python imaging library. From 11.0.0 until 13.0.0, Exif.load() in src/PIL/Image.py repeatedly slices the remaining EXIF data while it begins with the six-byte Exif header. src/PIL/PngImagePlugin.py accepts an uncapped PNG eXIf chunk, so a file filled with repeated headers causes a new shrinking copy on every iteration and quadratic CPU work. The condition is reachable through Image.getexif(), Image._getexif(), and ImageOps.exif_transpose(), including common photo-upload rotation workflows. This issue is fixed in version 13.0.0.
CVE-2026-96642:
Pillow is a Python imaging library. Prior to 13.0.0, the TarIO initializer in src/PIL/TarIO.py accepts a negative octal member size and computes a backward seek that returns to the same 512-byte header. When the requested member name does not match, the parser repeatedly reads that header, consumes a full CPU core, and never returns. TarIO is reached only when an application directly uses PIL.TarIO.TarIO rather than the default Image.open() path. This issue is fixed in version 13.0.0.
CVE-2026-96641:
Pillow is a Python imaging library. Prior to 13.0.0, PILfont text-width accumulation in src/_imaging.c checks positive glyph advances against INT_MAX but does not check negative advances against INT_MIN. Repeating a signed 16-bit advance of -32768 can therefore execute a signed C integer overflow in xsize += dx, producing a large positive width from a negative mathematical result. Applications that use getlength(), getsize(), or derived layout, quota, serialization, or allocation calculations can experience logic-integrity errors or resource consumption, while the high-level mask path commonly retains a decompression-bomb check. This issue is fixed in version 13.0.0.
CVE-2026-96640:
no details available
CVE-2026-96639:
Pillow is a Python imaging library. From 11.0.0 until 13.0.0, multi-frame loaders can retain an ImagingCore allocation created for a narrow frame mode while a later frame of the same dimensions changes the logical mode and decoder tiles to wider RGB or CMYK data. ImageFile.load_prepare() reuses the stale native storage because _im is non-null without verifying that its mode and size still match. Crafted PSD, MPO, DCX, or MIC frame transitions can then write wider pixels into the narrow allocation, causing native out-of-bounds writes and crashes. The MPO path can also cause a native over-read and, in demonstrated runtime-specific profiles, command execution. This issue is fixed in version 13.0.0.
CVE-2026-96638:
Pillow is a Python imaging library. From 9.1.0 until 13.0.0, BmpRleDecoder.decode() in src/PIL/BmpImagePlugin.py permits crafted RLE BMP delta escapes and absolute-mode runs to append beyond the remaining dest_length without a per-branch cap. A delta can add roughly 255 image rows in one iteration, so a kilobyte-sized file with a large but permitted width can expand the data bytearray to hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.
CVE-2026-96637:
Pillow is a Python imaging library. Prior to 13.0.0, SpiderImageFile.seek() in src/PIL/SpiderImagePlugin.py reparses a later SPIDER stack frame and replaces self._size without rerunning Image._decompression_bomb_check(). A tiny file can use a safe first frame to pass Image.open() and then declare very large dimensions in a later mode F frame. Loading that frame allocates approximately four bytes per attacker-declared pixel and can consume multiple gigabytes of memory. This issue is fixed in version 13.0.0.
CVE-2026-96636:
Pillow is a Python imaging library. Prior to 13.0.0, MpoImageFile.seek() and DcxImageFile.seek() reparse later MPO or DCX frames and replace self._size without rerunning Image._decompression_bomb_check(). A crafted multi-frame image can use a tiny first frame to pass Image.open() and then declare an over-limit later frame. Normal frame iteration through seek(), load(), or ImageSequence.Iterator can decode that frame and commit hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.
CVE-2026-114501:
Pillow is a Python imaging library. From 11.2.1 until 13.0.0, Arrow export assumes that an image's rows are tightly contiguous and exports from im->blocks[0].ptr even when PILLOW_ALIGNMENT makes aligned_linesize include row padding or an aligned offset before the first row. The resulting Arrow buffer can include uninitialized padding, bytes preceding the first row, or stale heap contents from previously freed images. Applications that configure alignment and export images to Arrow can therefore disclose one user's pixels or other process memory to another user. This issue is fixed in version 13.0.0.
CVE-2026-112901:
Pillow is a Python imaging library. Prior to 13.0.0, Pillow's XBM header parser is vulnerable to regular-expression denial of service. In XbmImageFile._open, when an application calls Image.open() on a small crafted XBM file, XbmImagePlugin applies a backtracking expression to the attacker-controlled header before image dimensions are accepted, stalling a worker for minutes and denying service. This issue is fixed in version 13.0.0.
CVE-2026-112900:
no details available
CVE-2026-112898:
Pillow is a Python imaging library. From 9.1.0 until 13.0.0, Pillow can disclose uninitialized stack memory when Image.quantize() uses an empty palette. ImagingPaletteCacheUpdate() leaves a local cache array uninitialized when the palette has zero entries, and the conversion path emits those bytes as output pixel indices. An attacker who controls the palette image can obtain stack contents from a returned PNG or GIF. This can disclose addresses and stack-canary data without an out-of-bounds access, memory corruption, or process crash. This issue is fixed in version 13.0.0.
CVE-2026-112897:
Pillow is a Python imaging library. From 5.3.0 until 13.0.0, Pillow can return uninitialized memory as pixels when libtiff performs a short decode of JPEG-compressed or Group 4 fax TIFF data. The _decodeStrip and _decodeTile buffers can be larger than the bytes written by libtiff, but Pillow converts the expected rows without clearing the unwritten tail. The tile path is affected from 5.3.0 and the strip path from 6.0.0. An attacker can supply a crafted TIFF to an application that loads and returns or re-encodes its pixels. This can disclose stale heap contents without memory corruption or a process crash. This issue is fixed in version 13.0.0.
CVE-2026-112896:
Pillow is a Python imaging library. Prior to 13.0.0, Pillow's TIFF encoder can read beyond a ColorMap buffer when retained TIFF metadata has a plane size inconsistent with BitsPerSample. A small TIFF can be opened normally and then retain a crafted ColorMap that is reused when the image is saved. An application that re-encodes the attacker's TIFF with libtiff can trigger the out-of-bounds read. This can disclose heap memory in the output or crash the process. This issue is fixed in version 13.0.0.
CVE-2026-112895:
no details available
CVE-2026-112894:
Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow takes quadratic time to reserve PDF object identifiers when saving many frames with save_all enabled. PdfParser.next_object_id() repeatedly rebuilds and scans all previously reserved identifiers for every object. An attacker can supply a multi-frame image, including a small APNG with a large declared frame count, to an application that converts it to a multipage PDF. This can consume excessive CPU and deny service. This issue is fixed in version 13.0.0.
CVE-2026-112893:
no details available
CVE-2026-112892:
no details available
CVE-2026-112891:
no details available
CVE-2026-112406:
no details available
CVE-2026-112405:
no details available
CVE-2026-112404:
no details available
CVE-2026-112403:
no details available
CVE-2026-112402:
no details available
CVE-2026-112401:
no details available
CVE-2026-112400:
no details available
CVE-2026-112399:
Pillow is a Python imaging library. From 8.1.0 until 13.0.0, Pillow can allocate an APNG disposal background at the full canvas size before applying the decompression-bomb check. A crafted APNG with a small first frame, a very large declared canvas, and background disposal or first-frame OP_PREVIOUS reaches PngImageFile._seek while Image.open() positions frame zero. The full-canvas allocation occurs inside Image.open() without requiring pixel loading or frame iteration. This can exhaust memory and deny service. This issue is fixed in version 13.0.0.
CVE-2026-112398:
no details available
CVE-2026-112397:
no details available
CVE-2026-112396:
no details available
CVE-2026-112395:
no details available
CVE-2026-112394:
no details available
CVE-2026-112393:
no details available
CVE-2026-112392:
Pillow is a Python imaging library. Prior to 13.0.0, Pillow's rank-based filters can dereference invalid image storage for a zero-size image. ImagingExpand() allocates a non-empty output and then faults while replicating edges by reading the first pixel from empty input storage; ImagingRankFilter is never reached. An attacker can supply or cause creation of a zero-size image to an application that applies a rank, median, minimum, or maximum filter. This causes a native process crash. This issue is fixed in version 13.0.0.
CVE-2026-112391:
Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow's PdfParser.get_value() can recurse without a limit while reading nested PDF objects. The parser follows attacker-controlled arrays and dictionaries when an existing PDF is opened for append. An attacker can provide a deeply nested PDF to an application that saves an image with PDF append enabled. This can raise an uncaught RecursionError or terminate the worker, causing denial of service. This issue is fixed in version 13.0.0.
CVE-2026-112390:
Pillow is a Python imaging library. From 7.2.0 until 13.0.0, Pillow can enter an infinite loop while determining the frame count of a MIC image. MicImageFile inherits TIFF frame traversal, but MicImageFile.tell reports the OLE stream index and its seek() resets TIFF frame state, so an embedded TIFF with at least three IFDs never advances. When an application with olefile installed reads n_frames or saves all frames from a crafted MIC file, the non-advancing traversal can hold a worker at full CPU indefinitely. This issue is fixed in version 13.0.0.
Affected Packages:
python-pillow
Issue Correction:
Run dnf update python-pillow --releasever 2027.0.20261102 or dnf update --advisory ALAS2027-2026-268 --releasever 2027.0.20261102 to update your system.
aarch64:
python-pillow-debugsource-13.0.0-1.amzn2027.0.1.aarch64
python3-pillow-tk-debuginfo-13.0.0-1.amzn2027.0.1.aarch64
python-pillow-debuginfo-13.0.0-1.amzn2027.0.1.aarch64
python3-pillow-devel-13.0.0-1.amzn2027.0.1.aarch64
python3-pillow-tk-13.0.0-1.amzn2027.0.1.aarch64
python3-pillow-debuginfo-13.0.0-1.amzn2027.0.1.aarch64
python3-pillow-13.0.0-1.amzn2027.0.1.aarch64
src:
python-pillow-13.0.0-1.amzn2027.0.1.src
x86_64:
python-pillow-debuginfo-13.0.0-1.amzn2027.0.1.x86_64
python-pillow-debugsource-13.0.0-1.amzn2027.0.1.x86_64
python3-pillow-devel-13.0.0-1.amzn2027.0.1.x86_64
python3-pillow-13.0.0-1.amzn2027.0.1.x86_64
python3-pillow-tk-13.0.0-1.amzn2027.0.1.x86_64
python3-pillow-debuginfo-13.0.0-1.amzn2027.0.1.x86_64
python3-pillow-tk-debuginfo-13.0.0-1.amzn2027.0.1.x86_64